The family of Jayden Parkinson are "heartbroken and devastated "following the discovery of a body yesterday evening in a cemetery, Thames Valley Police said this morning.
During a brief press conference the man leading the investigation, Detective Chief Superintendent Andy Murray, said: "We had prepared Jayden's family for the worst but I'm afraid nothing can prepare you for the loss of your child.
They had discovered what are thought to be the remains of the 17-year-old, who has been missing for more than two weeks, in a recently disturbed grave in the churchyard of All Saints Church, Didcot, Oxfordshire.
Detectives believe the young girl was murdered after she went missing on December 3.
A formal identification of the body has yet to take place, but her family have been informed and are being supported by specialist police officers.
The teenager, who had recently moved to Oxford, was last seen leaving Didcot railway station at 4.27pm on the day of her disappearance.
Police said there had been "no indication" she was alive, after revealing Jayden had not appeared to have used her mobile phone or accessed her bank account in the days since she had been reported missing.
Officers had previously issued an appeal for information about a man seen struggling with a suitcase just outside the village of Upton, at about 2am on Monday December 9.
The focus of an extensive and detailed search over the weekend had been a 2km area of farmland on the outskirts of the village - including woodland and derelict farm buildings -following reports of the sighting.
Officers said the same man was later seen with the same suitcase in the Lydalls Road area of Didcot - where All Saints is located - at about 3.30am the same day.
Police also confirmed that during the course of their murder investigation it had been suggested Jayden may have been pregnant at the time of her disappearance, although Mr Murray said they "had no way of confirming whether this is correct or not".
Jayden's former partner, 22-year-old Ben Blakeley, has been charged with her murder and perverting the course of justice. He is due to appear at Oxford Crown Court for a plea hearing on March 17 next year.
A 17-year-old boy, who cannot be named for legal reasons, has also been charged with perverting the course of justice between December 3 and December 10 by assisting in the disposal of Jayden's body and other evidence.
The force said in a statement that officers and forensic scientists will continue to work at the cemetery throughout the night and into the next day.
"Our thoughts are with Jayden's family at this extremely difficult and distressing time," Thames Valley Police said in the statement.
Additional reporting by PA