Teenager Jayden Parkinson, whose body was found in a freshly-disturbed grave, died from "pressure to the neck", police have revealed.
The 17-year-old was discovered in a recently-disturbed grave in the Great Western Cemetery next to All Saints Church in Didcot, Oxfordshire, in December.
An initial post-mortem examination proved inconclusive, leading to toxicology tests being carried out, Thames Valley Police said.
A police spokesman said: "Those results have now been received and Thames Valley Police can confirm that the cause of death is consistent with pressure to the neck.
"Jayden's family has been informed and specially-trained family liaison officers continue to support the family."
Jayden, from Oxford, was last seen leaving Didcot railway station on 3 December. Police received "significant and highly relevant information" which led them to focus on the graveyard.
The discovery of her body followed an intensive search, involving more than 100 officers, backed up by specialists from the National Crime Agency.
Jayden's ex-boyfriend Ben Blakeley, 22, has been charged with murdering her and perverting the course of justice.
Blakeley, of Christchurch Road in Reading, Berkshire, is due to appear at Oxford Crown Court for a plea hearing on 17 March.
A 17-year-old boy, who cannot be named for legal reasons, is charged with perverting the course of justice between December 3 and December 10 by allegedly helping to dispose of Jayden's body and other evidence.
A third person, a 48-year-old woman, from Didcot, Oxfordshire, was arrested last month, also on suspicion of perverting the course of justice, and she was later freed on police bail to 14 March.
Last month mourners paid their respects at Jayden's funeral service at St Martin's Church in Cheriton, close to her former home town of Folkestone, Kent.
Meanwhile, the Independent Police Complaints Commission (IPCC) said it was investigating the response of Thames Valley Police to a missing person report and their later actions following Jayden's disappearance.
IPCC associate commissioner Guido Liguori said: "This is a desperately sad case where a teenage girl has lost her life.
"Our investigators have met with Jayden's family to explain our role and investigation. I know my condolences will be of little comfort to them as they continue to grieve over their loss.
"Our investigation is examining the response of Thames Valley Police to the missing persons report, and whether the individual and collective decisions made by police officers or staff and the related actions were appropriate and proportionate in the circumstances.
"I am mindful that a murder investigation is continuing and therefore we must be cautious about the information we make public so as not to interfere with the ongoing criminal proceedings."