Gabby Petito's cause of death was ruled to be strangulation and the manner of death was homicide, Teton County Coroner Dr. Brent Blue announced on Tuesday.
He said that the time of Petito's death was estimated to be about three to four weeks before her body was found on September 19 in Bridger-Teton National Forest in Wyoming.
Today's announcement follows a string of developments in the case. On Sept. 22 the FBI in Denver confirmed that the remains found in Wyoming's Bridger-Teton National Forest were those by Petito, a 22-year-old woman who disappeared while on a trip exploring national parks with her fiancé, Brian Laundrie.
"Anyone with information concerning Mr. Laundrie's role in this matter or his current whereabouts should contact the FBI," Special Agent in Charge Michael Schneider said.
Petito had been traveling with Laundrie prior to her disappearance.
Local and federal authorities have been searching for him in a 25,000-acre Florida nature reserve. In late September, the FBI announced a federal arrest warrant was issued for Laundrie for his activities after Petito's death.
Here's what we know about the timeline in Petito's case:
June: Petito and Laundrie embarked on a cross-country trip, according to North Port Police Chief Todd Garrison, who refers to Laundrie as Petito's fiancé.
They planned to travel in Petito's white Ford van to the West Coast and visit state and national parks across the western United States, Garrison said at a news briefing.
She had been excited to share her journey with her family and others on social media, he said.
"She maintained regular contact with her family members during her travels; however, that communication abruptly stopped around the end of August," the police chief added.
Aug. 12: Moab, Utah, police had an encounter with the couple on Aug. 12, where officers described them as having "engaged in some sort of altercation."
Although the two were described as getting into a physical fight following an argument, "both the male and female reported they are in love and engaged to be married and desperately didn't wish to see anyone charged with a crime," a report from Officer Eric Pratt said.
At officers' suggestion, the couple separated for the night, according to the report, which described Petito as "confused and emotional."
"After evaluating the totality of the circumstances, I do not believe the situation escalated to the level of a domestic assault as much as that of a mental health crisis," Officer Daniel Robbins wrote in the report. No charges were filed.
The couple each had their own cell phones in case of emergency, the report added.
In a 911 audio recording from that day provided by the Grand County Sheriff's Office, a caller told dispatch he wanted to report a domestic dispute and described a white van with a Florida license plate.
The caller said as they were driving by, "the gentleman was slapping the girl."
"Then we stopped," the caller added. "They ran up and down the sidewalk. He proceeded to hit her, hopped in the car and they drove off."
Aug. 17: Laundrie flew to Tampa, Florida, from Salt Lake City on Aug. 17, according to Laundrie family attorney Steven Bertolino.
Laundrie "flew home to obtain some items and empty and close the storage unit to save money as they contemplated extending the road trip," Bertolino told CNN.
On Aug. 23, Laundrie returned to Salt Lake City to rejoin Petito, the attorney said, adding, "To my knowledge, Brian and Gabby paid for the flights as they were sharing expenses."
Read the full timeline here.
CNN's Eric Levenson contributed reporting to this post.