Barry Thompson was arrested in Basildon, Essex, on Monday, two weeks after he told The Mirror that his testimony was "a pack of lies".
Stone, 38, of Gillingham, Kent was convicted last month of murdering Dr Lin Russell, 45, and her daughter, Megan, six. He was also convicted of the attempted murder of Josie Russell, now 11.
Mr Thompson told Maidstone Crown Court details of a conversation he had with Stone when they were both in prison. But Mr Thompson contacted the press the day after the jury found Stone guilty, saying he wanted to retract the key part of this statement.
A Kent police spokesman said yesterday Mr Thompson had been sought for questioning over the matter, but had only been found this week. Hampshire police, a force unconnected with the Russell murder investigations, have now been asked by Kent to take over an inquiry into the allegations.
Mr Thompson has been released on bail and will be questioned at a later date.
Kent police said they were also "taking seriously" allegations at the weekend that other witnesses in the trial, Lawrence Calder and Sheree Batt, had been threatened and told to withdraw their evidence.
Stone, who had protested his innocence, has lodged an appeal against his convictions. In a letter to The Mirror published yesterday, he asked: "What they (the police) gonna do if they ever get an idea on who did kill the Russell family?"