Police searching for missing teenager Jayden Parkinson, who they believe has been murdered, have urged the public not to conduct their own searches.
Jayden, 17, was last seen mid-afternoon on the 3 December in the Iffley Road area of Oxford.
Two men aged 17 and 22 remain in police custody on suspicion of murder in connection with her disappearance.
“Due to the nature of the police searches taking place, we would request the public refrain from organising their own search activity at this stage to avoid the risk of jeopardising the investigation,” Commander Supt Christian Bunt said.
Detective Chief Superintendent Andy Murray said police were now focusing on trying to find a man who was seen with a large suitcase in a field in the small village of Upton in the early hours of 9 December.
“That suitcase was large, it was heavy, it was difficult to manage and that man was having difficulty removing that suitcase from that area,” he said.
Mr Murray said the same man with the suitcase was seen in nearby Didcot about half an hour later. Police investigations are now being focussed on the village of Upton and a grassed area off Lydalls Road in Didcot.
The man has been described as about 20, white, about 5ft 6in, of medium to slim build, with short dark hair. The suitcase was about 3ft by 2ft, about 15in deep and light coloured, probably made of canvas material.
Mr Murray said police were also searching addresses that Jayden “may be associated with”.
Mr Murray said officers were certain the man spotted in Upton with the suitcase was the same man seen shortly after in Didcot, but did not say why.
He said Jayden's family were still hoping for the best. “As you might imagine, they are distraught,” he said.
“They've still got hope but they are distraught and they want their daughter to come home.”
But Mr Murray said the fact Jayden had not used her phone or accessed her bank account since the disappearance could indicate a worse scenario.
“I'm afraid the detective in me leads me to conclude that Jayden may well have been murdered and that's why we have approximately 50 detectives out there still trying to find Jayden, still trying to find evidence that might lead to somebody being convicted if she has been murdered,” he said.
Jayden is white, of slim build with shoulder-length dark brown hair and brown eyes. She was wearing light blue faded jeans, a brown hooded top with red lettering on it, a black waist-length jacket, and dark trainers when she was last seen.
It is believed she walked up the High Street through the town centre, arriving at Oxford train station at 4.07pm, where she boarded a train to Didcot. The last sighting of her is when she left Didcot train station at about 4.27pm.