Professor David Wilson claims he has gathered evidence that could shed fresh light on at least three unsolved UK murders.
He has reportedly linked Tobin to the death of Jessica Earl, an art student who disappeared from her bedsit in Eastbourne, East Sussex, in 1980. Her remains were found nine years later.
The Glasgow-born academic looked at other unsolved murders in locations where Tobin has lived that bear similar hallmarks.
Professor Wilson said: "When Tobin was in custody in Peterhead prison he is alleged to have boasted to a psychologist that he has killed 48 women.
"There is one piece of empirical criminological evidence, however, that encouraged me to take his boast seriously.
"We know that murder, generally, and serial killing specifically, is a young man's business.
"Most serial killers begin to murder in their twenties. We know Peter Tobin killed Angelika Kluk when he was nearly 60. That is extra- ordinary unusual behaviour. You have 40 years therefore, potentially, in which to try and see if his lifeline corresponds with cold cases."
Mr Wilson will present his theories in an episode of the Channel 5 documentary series, Killers Behind Bars: The Untold Stories, to be shown on Tuesday.
The criminologist – who earlier linked Tobin with the Bible John murders of the 1960s – stressed he was merely testing a hypothesis in an academic context.
He said: "I don't claim to be a policeman, I don't claim to be putting this evidence before a judge and a jury. What I hope to achieve – the objective of the programme – is to encourage these cold cases to be warmed up."
The criminologist filmed at St Patrick's RC Church in Anderston, Glasgow, where 23-year-old Polish student Angelika Kluk was raped and murdered in 2006, and in the garden of Tobin's former home in Margate where he buried the remains of Dinah McNicol and Vicky Hamilton in 1991.
The series will later focus on Grangemouth-born serial child killer Robert Black, who is serving life imprisonment for the murders of Susan Maxwell, Caroline Hogg, Sarah Harper and Jennifer Cardy. He has additional con-victions for kidnap and attempted kidnap.
Mr Wilson believes he has uncovered two cold cases involving children that require urgent reinvestigation. He added: "I do believe he has killed more. I have no doubt."
Killers Behind Bars: The Untold Stories is on Channel 5, 8pm, on Tuesday