Two men have been arrested over the disappearance of Doncaster teenager Andrew Gosden 15 years ago.
A 45-year-old man was arrested on suspicion of kidnap, human trafficking and the possession of indecent images of children.
A 38-year-old man was arrested on suspicion of kidnap and human trafficking.
The arrests were carried out in London by officers from South Yorkshire Police and the Metropolitan Police on Wednesday, 8 December.
Both have now been released under investigation while enquiries continue.
Today, Andrew's father, Kevin, told ITV News he had been given no further information about the background to the arrests.
Andrew Gosden's father Kevin speaks to Duncan Wood
"We're not able to reach any conclusion about it, so for us it's just another unknown that's hard to cope with," he said.
He added that the impact of Andrew's disappearance had been "huge".
He said: "Since Andrew went missing, I've struggled with a lot of mental health problems – depression, anxiety and so on – and the emotional toll for the family is massive and it is very much the not knowing, that you can't reach any conclusion. Recent events are just a repetition of that."
Andrew would now be 28. He disappeared on 14 September, 2007 after boarding a train from Doncaster to London.
Senior investigating officer, Detective Inspector Andy Knowles, said: "Our priority at this time is supporting Andrew’s family while we work through this new line of enquiry in the investigation.
"We are in close contact with them and they ask that their privacy is respected as our investigation continues.
"We have made numerous appeals over the years to find out where Andrew is and what happened to him when he disappeared. I would encourage anyone with any information they have not yet reported to come forward."