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Kiev, Ukraine (CNN) -- Did a Russian fire the missile that downed Malaysia Airlines Flight 17? That depends on who you ask.
A top Ukrainian official says he has no doubt.
Vitaly Nayda, Ukraine's director of informational security, told CNN the person who shot down the flight was "absolutely" a Russian. "A Russian-trained, well-equipped, well-educated officer ... pushed that button deliberately," he said.
"We taped conversations" between a Russian officer and his office in Moscow, Nayda said. "We know for sure that several minutes before the missile was launched, there was a report" to a Russian officer that the plane was coming, he said.
"They knew the plane was coming with constant speed, in constant direction," and should have known it was not a fighter jet but "a big civilian plane," he said.
Does debris prove MH17 was shot down?
Who leads the pro-Russian rebels?
U.S. officials say pro-Russian rebels were responsible for shooting down Malaysia Airlines Flight 17, but they now believe it's likely the rebels didn't know the plane was a commercial airliner when they opened fire, U.S. intelligence officials said Tuesday.
Families of crew members aboard Malaysia Airlines Flight 17 gather for a vigil Tuesday, July 22, in Kuala Lumpur, Malaysia. All 298 people aboard the passenger plane died when it was shot down Thursday, July 17, in a rebel-controlled part of eastern Ukraine.
Photos: Reaction to MH17
MH17 bodies arrive in Kharkiv
MH17 black boxes handed over to Malaysia
The officials have determined that Russia bears some responsibility for the incident because of its support for the rebels, but they haven't been able to determine exactly who fired the missile, whether Russian military were at the site or whether the Russians were directly responsible for launching the missile.
Moscow has denied claims that it pulled the trigger. And Russian Army Lt. Gen. Andrei Kartapolov suggested a Ukrainian jet fighter may have shot the plane down.
Ukrainian President Petro Poroshenko rejected that in an exclusive interview with CNN, saying that all Ukrainian aircraft were on the ground at the time.
Vitaly Churkin, Russia's ambassador to the United Nations, was asked Monday about different intercepted recordings, purportedly of pro-Russian rebels talking about shooting down a plane. Churkin suggested that if they did, it was an accident.
"According to them, the people from the east were saying that they shot down a military jet," he said. "If they think they shot down a military jet, it was confusion. If it was confusion, it was not an act of terrorism."
Pro-Russian rebels have repeatedly denied responsibility for the attack.
At crash site, an eerie calm
Now that rebels have handed over the black boxes and the bodies of victims killed when Flight 17 went down, the crash site in eastern Ukraine was eerily quiet on Tuesday, a spokesman for observers in the area said.
There were no more local emergency workers or teams combing the wreckage -- even though Dutch officials said they weren't sure whether the remains of all the victims had been recovered.
"They had even taken down the tents," said Michael Buciurkiew, spokesman for the monitoring mission from the Organization for Security and Cooperation in Europe. "There was no activity whatsoever. ... We had an internal discussion today on whether to say it's already trending towards a cleanup operation. There's no active recovery of remains going on right now."
As investigators arrive at the scene, it's unclear what evidence they'll find.
Before activity died down at the site, Buciurkiew said, observers saw emergency workers moving around wreckage.
"Major pieces of the fuselage have been moved," he said.
At one point, he said, observers witnessed teams at the scene "taking out diesel-powered saws and sawing quite invasively into the cockpit."
Dutch PM: Identifying bodies could take months
A train carrying the remains of crash victims arrived in Kharkiv, Ukraine, on Tuesday.
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Debris from Malaysia Airlines Flight 17 sits in a field at the crash site in Hrabove, Ukraine, on Tuesday, September 9. The Boeing 777 is believed to have been shot down July 17 in an area of eastern Ukraine controlled by pro-Russian rebels.
Malaysia Airlines jet crashes in Ukraine
Investigators were going through the train cars and transferring bodies to a factory, where a facility was set up to transfer them to coffins and get them on a military plane to the Netherlands for forensic investigation.
But officials offered conflicting reports about how many bodies were on the train, with a top Dutch official expressing concern that the remains of more victims could still be at the crash site.
Malaysian official Mohd Sakri, who traveled on the train with the remains, said there were 282 corpses and 87 body parts aboard -- the same tally Ukrainian officials earlier gave to describe the remains recovered from the crash site.
But Dutch investigators only confirmed there were at least 200 bodies transported from the crash site, Jan Tuinder, head of the Dutch delegation, told reporters. Another Dutch official said investigators were still going through the train cars and it was possible all the crash victims were on the train.
There were 298 people aboard the plane when it crashed.
Dutch Prime Minister Mark Rutte said he expects the first plane carrying the remains to arrive Wednesday in Eindhoven.
As soon as the remains are identified, families of the victims will be informed. In some cases, that could happen quickly, Rutte said, but in other cases, identification could take weeks or even months.
Frans Timmermans, the Dutch foreign minister, said bringing the victims' remains home is his country's top priority.
"To my dying day, I will not understand that it took so much time for the rescue workers to be allowed to do their difficult jobs," he told the U.N. Security Council on Monday, "and that human remains should be used in a political game."
What's next in the investigation?
Ukrainian rebels handed over the so-called black boxes Tuesday after what Malaysian officials said were repeated attempts to negotiate with the rebels.
"In recent days, we have been working behind the scenes to establish contact with those in charge of the MH17 crash site," Malaysian Prime Minister Najib Razak said Monday.
But the handover is only the beginning.
British Prime Minister David Cameron tweeted that Britain agreed to a Dutch request for accident investigators at Farnborough, southwest of London, to retrieve data from the boxes for international analysis.
And the U.S. National Transportation Safety Board said one of its experts will help retrieve information from the black boxes.
The voice recorder could include audio from the cockpit, which would show whether the pilots knew the plane had been hit, said Mary Schiavo, a CNN aviation analyst and former inspector general for the U.S. Department of Transportation.
And the flight data recorders will give investigators information about engine settings, pressurization and electronic communications, among other details, she said.
But even the black boxes might not answer the two most pressing questions: who shot down the plane and why.
A woman cries July 22 during a service near the crash site.
People in Melbourne gather to mourn the victims during a candlelight vigil at Federation Square on July 22.
In memory of two Newcastle United fans who died in the crash, two wreaths are placed on seats July 22 at the Forsyth Barr Stadium in Dunedin, New Zealand. The soccer fans were traveling to New Zealand to watch their team play in a preseason tournament.
A KLM employee reaches out into a sea of flowers July 22 at Schiphol Airport in Amsterdam, Netherlands.
A flower and stuffed animal sit near the crash site on Monday, July 21.
A woman in Kuala Lumpur attends a candlelight vigil on July 21.
Ukrainian President Petro Poroshenko attends a flower-laying ceremony at the Dutch Embassy in Kiev, Ukraine, on July 21. Although the passengers came from all over the world, many of them were Dutch because the flight originated in Amsterdam.
A woman places a flower during a candlelight vigil in Kuala Lumpur on July 21.
Mourners in Eynesbury, Australia, attend a memorial service Sunday, July 20, for a family of five killed in the disaster.
Buddhist monks in the Malaysian capital light candles during a special prayer for the victims on July 20.
Wildflowers lie on an engine from the crashed jet on Saturday, July 19.
Friends of Nur Shazana Mohamed, a crew member aboard the flight, take part in a special remembrance prayer at a mosque in Putrajaya, Malaysia, on July 19.
Dutch Prime Minister Mark Rutte signs a condolence register at the Ministry of Safety and Justice in The Hague, Netherlands, on Friday, July 18. "I want to see results in the form of unimpeded access and rapid recovery," Rutte said in a press briefing. "This is now priority number one."
People pray for the victims of Malaysia Airlines Flight 17 at a church outside Kuala Lumpur on July 18.
A woman in Berlin places a candle at a memorial on July 18.
People in Kiev gather to mourn the victims on July 18.
Akmar Binti Mohd Noor, whose sister was aboard Flight 17, cries outside the family holding area at Kuala Lumpur International Airport on July 18.
A man prays at a memorial in front of the Dutch Embassy in Kiev on July 18.
Dutch cyclists wear a black armband in honor of the crash victims during the 13th stage of the Tour de France on July 18.
Dutch Justice Minister Ivo Opstelten observes a moment of silence after signing a condolence book in The Hague on July 18.
Candlelight prayers honor the victims at a church outside Kuala Lumpur on July 18.
Floral tributes adorn the entrance to Schiphol Airport in Amsterdam.
A Dutch flag flies at half-staff in The Hague on July 18.
People place flowers in front of the Dutch Embassy in Moscow on July 18.
Students attend a prayer July 18 in Central Java, Indonesia. Their teacher John Paulissen was a passenger on Flight 17.
Russian President Vladimir Putin, center, and members of his government observe a moment of silence on Thursday, July 17.
People pay tribute to the victims outside the Dutch Embassy in Kiev on July 17.
Australian and Dutch experts examine the area of the crash on Sunday, August 3.
A woman walks with her bicycle near the crash site on Saturday, August 2.
Police secure a refrigerated train loaded with bodies of passengers from Malaysia Airlines Flight 17 as it arrives in a Kharkiv, Ukraine, factory on Tuesday, July 22.
A pro-Russian rebel passes wreckage from the crashed jet near Hrabove on Monday, July 21.
Wreckage from the jet lies in grass near Hrabove on July 21.
A man covers his face with a rag as members of the Organization for Security and Co-operation in Europe and the Dutch National Forensic Investigations Team inspect bodies in a refrigerated train near the crash site in eastern Ukraine on July 21.
Emergency workers carry a victim's body in a bag at the crash site on July 21.
A piece of the plane lies in the grass in eastern Ukraine's Donetsk region on July 21.
An armed pro-Russian rebel stands guard next to a refrigerated train loaded with bodies in Torez, Ukraine, on Sunday, July 20.
Ukrainian State Emergency Service employees sort through debris on July 20 as they work to locate the deceased.
A woman covers her mouth with a piece of fabric July 20 to ward off smells from railway cars that reportedly contained passengers' bodies.
Toys and flowers sit on the charred fuselage of the jet as a memorial on July 20.
People search a wheat field for remains in the area of the crash site on July 20.
A woman walks among charred debris at the crash site on July 20.
Emergency workers load the body of a victim onto a truck at the crash site on Saturday, July 19.
Emergency workers carry the body of a victim at the crash site on July 19.
A large piece of the main cabin is under guard at the crash site on July 19.
Victims' bodies are placed by the side of the road on July 19 as recovery efforts continue at the crash site. International officials lament the lack of a secured perimeter.
A man looks through the debris at the crash site on July 19.
An envelope bearing the Malaysia Airlines logo is seen at the crash site on July 19.
Armed rebels walk past large pieces of the Boeing 777 on July 19.
Ukrainian rescue workers walk through a wheat field with a stretcher as they collect the bodies of victims on July 19.
A woman looks at wreckage on July 19.
Pro-Russian rebels stand guard as the Organization for Security and Co-operation in Europe delegation arrives at the crash site on Friday, July 18.
A woman walks through the debris field on July 18.
Pro-Russian rebels stand guard at the crash site.
Wreckage from Flight 17 lies in a field in Shaktarsk, Ukraine, on July 18.
A man covers a body with a plastic sheet near the crash site on July 18. The passengers and crew hailed from all over the world, including Australia, Indonesia, Malaysia, Germany and Canada.
A diver searches for the jet's flight data recorders on July 18.
Coal miners search the crash site.
Wreckage from the Boeing 777 lies on the ground July 18.
People search for bodies of passengers on July 18.
A woman walks past a body covered with a plastic sheet near the crash site July 18.
Belongings of passengers lie in the grass on July 18.
People inspect the crash site on Thursday, July 17.
People walk amid the debris at the site of the crash.
Debris smoulders in a field near the Russian border.
Fire engines arrive at the crash site.
A man stands next to wreckage.
Debris from the crashed jet lies in a field in Ukraine.
Family members of those aboard Flight 17 leave Schiphol Airport near Amsterdam, Netherlands.
A large piece of the plane lies on the ground.
Luggage from the flight sits in a field at the crash site.
A couple walks to the location at Schiphol Airport where more information would be given regarding the flight.
Flight arrivals are listed at the Kuala Lumpur International Airport in Sepang, Malaysia.
Debris from the Boeing 777, pictured on July 17.
A man inspects debris from the plane.
Wreckage from the plane is seen on July 17.
A man talks with security at Schiphol Airport on July 17.
Wreckage burns in Ukraine.
A man stands next to the wreckage of the airliner.
People inspect a piece of wreckage believed to be from Malaysia Airlines Flight 17. This image was posted to Twitter.
People inspect a piece of wreckage believed to be from Malaysia Airlines Flight 17. This image was posted to Twitter.
A piece of wreckage believed to be from Malaysia Airlines Flight 17. This image was posted to Twitter.
A piece of wreckage believed to be from MH17. This image was posted to Twitter.
An airsickness bag believed to be from MH17. This image was posted to Twitter.
A piece of wreckage believed to be from MH17. This image was posted to Twitter.
Here is satellite trajectory of #FlightMH17 and the missile US says shot it down. @NatSecCNN @cnnbrk pic.twitter.com/ijsUM1nCjZ
— Barbara Starr (@barbarastarrcnn) July 22, 2014U.S. and other officials have said it appears the plane was shot down by a sophisticated surface-to-air missile in rebel-held territory. Evidence supporting that conclusion includes telephone intercepts and video of a Buk missile launcher traveling into Russia with at least one missile missing.
U.S. President Barack Obama, Cameron and others have said the pro-Russian rebels could not have shot down such a high-flying jet without weapons and training from Russia.
Obama called on Russia to rein in the rebel fighters, who he said had treated remains poorly and removed evidence from the site. "What exactly are they trying to hide?" he said.
Steward swapped flights to get on MH17
Ukraine Pres gets heated over Russia claim
Russian President Vladimir Putin said Tuesday that his country would use its influence with Ukrainian rebels to push for a full investigation, the Reuters news agency reported.
But those assurances did little to stem efforts to crack down on the rebels and their supporters.
The European Union's Foreign Affairs Council agreed Tuesday to establish a new list of entitles and individuals, including some from Russia, to face EU sanctions.
Timmermans said the Netherlands would seek sanctions involving various fields, including defense, high technology, the energy sector and financial services.
A brawl broke out Tuesday in Ukraine's parliament, where fighting takes place frequently, as lawmakers voted to increase the number of troops battling pro-Russian rebels.
Nikolai Levchenko, who is from the Donetsk region and has been noticed at separatist rallies, accused the government of killing its own people. A nationalist lawmaker then ran up to him. Soon many lawmakers swarmed around them, with some apparently trying to break up the fight.
Ukraine opens criminal case
The U.S. government has released a map of what it says was the flight's path and the site from which the missile was fired. It also released images that it said showed a weapons buildup at a Russian training facility near the Ukraine border.
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As Ukraine ratcheted up accusations that Moscow was involved in downing the plane, it also opened criminal cases against Russia's defense minister and a Russian businessman, calling both "accomplices of terrorists."
The Ukrainian Internal Affairs Ministry accused Russian Defense Minister Gen. Sergei Shoigu of helping form "illegal military groups" in the Donetsk region, where pro-Russian rebels have declared their own government.
"The illegal military groups, which are led by citizens of the Russian Federation, make regular attacks on government institutions and other organizations that have led to multiple human deaths, destruction and other consequences," the ministry said in a statement.
And the ministry accused Russian billionaire Konstantin Malofeev of financing the "illegal military units."
Russian officials have repeatedly denied involvement in fomenting violence in the region.
A June profile on Malofeev by Bloomberg News noted that the "self-proclaimed head of the unrecognized Donetsk People's Republic and its rebel army leader have both worked for Malofeev, though the financier denies any role in the unrest."
Earlier this month, Ukraine opened a criminal case against the head of Russia's Border Service.
The ministry's statement Tuesday contained no specific references to the downing of Malaysia Airlines Flight 17.
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CNN's Kyung Lah reported from Kiev; Josh Levs and Catherine E. Shoichet reported from Atlanta; and CNN's Nick Paton Walsh, Holly Yan, Carol Jordan, Pamela Boykoff, Phil Black, Gul Tuysuz, Elizabeth Joseph, Stephanie Halasz, Antonia Mortensen, Barbara Starr and journalist Victoria Butenko contributed to this report.
