Cold case detectives have arrested a man on suspicion of murdering a six-year-old boy more than 20 years ago.
Rikki Neave was last seen leaving his home on the Welland estate in Peterborough to go to school on November 28 1994.
His naked body was found in nearby woodland the following day. A post-mortem examination found he had been strangled.
In a statement on Tuesday morning, Cambridgeshire Police said they had arrested a man, aged in his 30s and from Peterborough, on suspicion of murder.
A spokesman said: "He is currently in custody at a police station in Cambridgeshire."
Rikki's mother Ruth Neave, now 45, was charged with murder at the time but she was later found not guilty by a jury. She pleaded guilty to child neglect and cruelty and was sentenced to seven years in prison.
In recent years she has campaigned for Cambridgeshire Police to reinvestigate the case, saying his killer remains at large.
Anyone with information about Rikki's death should contact police on 01480 425882, email email@example.com or contact Crimestoppers anonymously on 0800 555 111.
Ms Neave called a press conference in 2014 to urge the force to reopen their investigation.
She said: ''I loved Rikki, he was a wonderful child.
''For the last 20 years, I have been going through living hell from the public opinion of me caused by all the lies.
''I wasn't a perfect mother but I never hurt my children and I should never have admitted to those offences.
''All I want now is justice and for his killers to be caught.
''I know people out there think I'm a murderer but I'm determined to prove that somebody else did this to my boy.''