A missing teenager last seen jumping from a ferry may have lept into the icy waters for a £100 bet.
Jordan Cobb, 16, was intending to take part in a New Year's Eve street party in Torpoint, Cornwall, after catching the ferry from Plymouth in Devon. He was last seen jumping from the ferry at 9pm that night.
After scanning social media and speaking to other witnesses, police say they believe the incident may be a "prank gone wrong".
There are hopes that the Stoke Damerel Community College student will be found alive
Detective Inspector Nick West said "We know that there was a discussion between the group about something - we understand that for some reason Jordan has given his bag to a friend, he's jumped up on to the front of the ferry and then jumped into the water.
"There is information in the public domain that suggests this is all a prank, that someone within Jordan's group has engaged with them in relation to a bet.
"We do understand that the figure of about £100 has been discussed, but that hasn't been confirmed. That's one line of inquiry that we're keeping an open mind on."
Specialist dive teams, the coastguard and the Ministry of Defence took advantage of low tides today to continue the search for the Stoke Damerel Community College student.
Jordan's friends had previously scanned sections of the coastline from the shore in an attempt to find him, as well as bombarding social media sites with calls to keep up the search.
Devon and Cornwall Police said they maintain hope of finding the teenager alive, despite the hunt for him entering a 10th full day.
Mr West added: "It is still a missing persons inquiry. Obviously, we will keep all hope that Jordan is out there alive and well.
"If this is a prank that's gone not wrong, he's jumped into the river and he's embarrassed to the fact he's caused all this commotion and all this activity, his friends' involvement and his family's distress - [if] he's just hiding low somewhere, then I would appeal for him to come forward.
"As time goes by, we have to be realistic. We will never forget that he is missing. If this is a tragic act that's gone wrong, then lessons need to be learned from it."