Police searching for a missing boy last seen leaping from a ferry into a river between Devon and Cornwall believe he may have jumped into the icy waters over 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.
But the alarm was raised shortly after 9pm when Jordan disappeared beneath the surface of the River Tamar, around 70 yards from the shore.
Police say they are still trying to track a handful of people who are believed to have been with Jordan in the moments leading up to his disappearance.
They have been scanning social media and speaking to other witnesses, and say they believe the incident may be a "prank gone wrong".
Detective Inspector Nick West said: "We know that there was a discussion between the group about something - we're still waiting for some people to come forward and clarify what went on - but 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."