Revenge likely motive in judge killings case
Suspect killed self; DNA, shell casings tie him to scene
Police check the van in which Bart Ross shot himself to death outside of Milwaukee, Wisconsin.
Suspect in murders of judge's husband, mother commits suicide.
West Allis police answer questions about man who committed suicide.
Chicago Tribune's Jim Warren discusses suicide note.
CHICAGO, Illinois (CNN) -- While Chicago authorities insist that their probe of the slayings of a judge's husband and mother remains open, more evidence is pointing to Bart Ross, a man who committed suicide after leaving a note confessing to the killings.
Ross apparently had filed a medical malpractice lawsuit that eventually was dismissed by the judge.
The new evidence pointing toward Ross: His DNA was found at the crime scene, police say, and a shell casing found at Ross' home matches casings found at the judge's home, where the slayings occurred.
Ross shot himself to death Wednesday night after police stopped his van in West Allis, Wisconsin, outside Milwaukee. His suicide note also included information that may confirm his presence in federal judge Joan Humphrey Lefkow's home the day of the killings, Chicago Police Superintendent Phil Cline said.
Despite the new evidence, Cline said the investigation into the slayings of Michael Lefkow, 64, and Donna Grace Humphrey, 89, would go on.
"We are not prepared at this time to say that any one person is responsible for these homicides," Cline said. "This case is by no means closed."
According to Chicago police, Ross' DNA matches the DNA found on a cigarette at the scene of the killings. Police sources also told CNN that a shell casing found at the Ross home matches shell casings found at the judge's residence.
Judge Lefkow found the bodies of her husband and mother Feb. 28 at her home on Chicago's north side. The note found with Ross included "things that weren't in the media" about the killings, Cline said.
Report: Note disclosed location of victim's body
The Chicago Tribune reported Thursday that the suicide note in Ross' van disclosed the location of Michael Lefkow's body, which police had not released. The Illinois state crime lab and the FBI crime lab were conducting DNA and fingerprint testing, Cline said.
In the suicide note, Ross blamed a legal judgment for the loss of his house, job and family, police told CNN. A neighbor told CNN that Ross, an electrical contractor, had been seen in the neighborhood a few weeks ago, but investigators told CNN police are looking into the possibility he was living in his minivan.
The Tribune reported Thursday that Lefkow had dismissed a medical malpractice case Ross filed against the University of Illinois in which he represented himself. Ross was unhappy over the results of treatment he had received for cancer of the jaw.
Authorities had been planning to interview Ross -- as one of many people whose cases had been handled by Lefkow -- but had not done so, Cline said.
Suits dealt with suspect's cancer treatment
A neighbor, Mercedes Riverda, said Ross was frustrated with hospitals, doctors and the judicial system.
"He came to my house and told me about it," Riverda said. "He wanted me to lend him some money, and he was having problems with the lawsuit ... None of the courts would listen to him, and everybody turned him away. He was pretty frustrated."
The University of Illinois Medical Center in Chicago said Ross first became a patient in 1992, when he was treated for head and neck cancer. He filed "numerous lawsuits" against the medical center, "all of which were dismissed."
"He received a series of treatments for his malignancy that were conservative and appropriate," the hospital said in a statement. "Mr. Ross was fully informed of the risks, benefits and alternative treatment options at all stages of his care, and he provided full, written consent at every step."
The treatment was successful, and Ross was cancer-free when last treated in 1995, the university said -- but "the treatment, while successful, does cause some disfigurement."
Ross' landlord had filed a petition to evict him, said Bill Cunningham, a spokesman for the Cook County Sheriff's Department. Deputies tried to serve Ross with the petition on March 1 and March 3, but received no answer when they came to the door, Cunningham said.
Wednesday night, Ricky Orlowski, a police officer in West Allis -- about an hour north of Chicago -- saw a man in a minivan parked near a school and noticed he appeared to be writing something, Police Chief Dean Puschnig said.
When Orlowski drove by a second time, the man did a U-turn and attempted to leave the area. Orlowski noticed the van, which had Illinois plates, had no tail lights and pulled it over.
"I just started to bring my head forward to the window because he hadn't rolled it down," Orlowski said. "I was thinking maybe he didn't see me behind him right away. All of a sudden, the gunshot came out. I felt a concussion. Glass hit me in the face. I was like, 'That guy just shot at me.' "
He said he drew his weapon, retreated to his cruiser and when he looked back at the minivan, he noticed that Ross was slumped over.
Cline said Chicago police did not know why Ross was in Milwaukee or how, if he were responsible for the Lefkow slayings, he had obtained the judge's address. He had no criminal record in Chicago or nationally, Cline said.
Police have searched Ross' home for any evidence, and are attempting to find out as much as they can about him, Cline said. Authorities have not been able to locate any family members, and asked anyone with information to contact Chicago police, the FBI or the U.S. Marshals Service.
Letter: 'I regret killing ... '
Meanwhile, in a letter received Wednesday by a Chicago television station, excerpts of which were released by WMAQ-TV, a person claiming to be Ross writes, "I regret killing husband and mother of Judge Lefkow as much as I regret that I have to die."
The letter writer claimed he encountered Michael Lefkow first and killed him, then heard Humphrey calling her son-in-law and shot her, too. He said he fired two bullets into each of his victims' heads.
"When you read this, I should be dead, so I am writing in past tense," said a typed statement accompanying the letter. "I was on my way to justice. For over 12 1/2 years I was violated the way Nazis and terrorist(s) violated people's rights and I was deprived 'to live' my life."
The letter then lists doctors, attorneys and state and federal judges, including Lefkow, and calls them an expletive, "because they are all criminals like Nazis and terrorists like bin Laden and al Qaeda and don't know 'how to let live.'"
Neither the television station nor the Tribune could verify the letter's authenticity. The station said it turned the letter over to authorities.
Cline said police were contacting the other people named in the letter, but said none of them had been injured.
The Tribune reported that police also found 300 .22-caliber bullets in Ross' van -- the same caliber as casings found in the Lefkow home, Warren said. Cline would not comment on the weapons found or their caliber.
As part of their investigation, police had been looking into the possibility that white supremacist leader Matt Hale, 33, may have been involved in the deaths. He was convicted in 2004 of trying to have the judge killed over a ruling in a trademark dispute, and is jailed awaiting sentencing. Hale has denied involvement.
Cline said Thursday that Ross apparently had no link to white supremacists. "At this point, we cannot find anyone else that's connected with (Ross)," he said.
Police earlier had released composites of two men they believed might have been involved in the homicides. One of those, a sketch of an older man, is believed to be Ross, Cline said. A witness saw that man leaving the Lefkow home sometime early in the afternoon, which matches a time the letter writer claimed to have left the home, police said.
CNN's Keith Oppenheim contributed to this report.