Operation Anagram was formed by Strathclyde Police in 2006 after Tobin raped and murdered 23-year-old Polish student Angelika Kluk in Glasgow.
It also helped convict him of the murders of 18-year-old Dinah McNicol and 15-year-old Vicky Hamilton.
Police said that while the operation was being scaled back it would never end.
Det Sup David Swindle, who formed the operation, said anyone with information regarding Peter Tobin would still be able to contact the Anagram incident room via e-mail which would be monitored daily.
"Since Operation Anagram was formed in 2006, I could never have believed the momentum and magnitude it would have developed into," he said.
"The public response and assistance from the media has been unbelievable.
"The long-running investigation has brought some solace to the families of Vicky Hamilton and Dinah McNicol in knowing what happened to their loved ones."
Det Sup Swindle said that although Anagram had not uncovered other murder victims of Tobin to date, he was "proud" of its "success in bringing closure" to some bereaved families.
He added: "I leave Strathclyde Police after 34 years in the knowledge that we have tried our best to find out the truth of what Tobin has done and also with confidence that the Anagram processes built up over the last four and a half years ensures a life long awareness of this cowardly, vicious serial killer Tobin.
"Any new information coming to light will continue to be researched which may bring similar closure to other families.
"The search for the truth about what Peter Tobin has done will continue."
Tobin is serving three life sentences for the murders of Vicky Hamilton, Dinah McNicol and Angelika Kluk.
Ms Kluk was raped and murdered at a church in Glasgow in 2006.
The bodies of Ms McNicol, from Essex, and Ms Hamilton, from Redding in Falkirk, were found the following year in the garden of Tobin's former home in Margate, Kent.
Operation Anagram has helped piece together a timeline of Tobin's movements and relationships over decades in a bid to determine whether he is responsible for other unsolved crimes.
A dedicated police operation set up to examine the activities of serial killer Peter Tobin is to be wound down.