Ivan Milat, the notorious Australian serial killer, died in 2019, but Australia’s leading crime experts say he might be responsible for up to 20 unsolved murders.

In  7NEWS Presents Ivan Milat: Buried Secrets, criminologist Dr Xanthe Mallett and criminal psychologist Tim Watson-Munro believe that Milat took other secrets to his grave.

The pair in the show look at unsolved murders and disappearances and compare them to known locations and sightings of Milat when he was alive.

Watson-Munro said that after their investigation, he is “sure” that Milat is responsible for six other murders and is “firm” that he was behind a range of others.

One of Milat’s potential victims was 20-year-old Keren Rowland, who was five months pregnant after her body was found in the Fairbairn Pine Plantation in Canberra in May 1971.

Dr Mallett said “the victimology, the type of victim, the circumstances under which she was taken and perhaps most importantly, the circumstances in which she was found,” led her to believe Milat was responsible for her death.

“It was so similar to Belanglo… it really spoke to us to have the same hallmarks of the Ivan Milat victims that we know of,” she explained.

Watson-Munro described Milat as “a psychopath and a marauding serial killer with no remorse” who “clearly enjoyed” killing people.

Keren Rowland is just one of a number of missing people, homeless people and runaways whose disappearances or murders are investigated in the show.

Milat was serving seven life sentences for the seven backpackers he killed before he died from terminal stomach and esophagus cancer in 2019.

Photo credits:  7NEWS