Former top police negotiator Lance Burdett has told SUNDAY that convicted killer George Baker was haunted by nightly "visions" of his victim.
Baker was convicted of murdering 17-year-old Liam Ashley in the back of a prison van in 2006, and sentenced to 18 years.
In 2009 Lance Burdett was called to Paremoremo prison where Baker had taken a fellow inmate hostage, on the anniversary of Ashley's death.
Prison guards told him that Baker had "done similar things on each of the two previous anniversaries", and had set up a kind of shrine to Ashley.
"We found out that every night Liam 'visited' Baker in his cell," says Mr Burdett.
He believes guilt, "pure and simple", was the motivating factor behind Baker's behaviour.
Last year, in a ONE News exclusive, Ashley's parents, Lorraine and Ian, said that they had since forgiven Baker and wanted to help him.
To hear more about Lance Burdett's career as a negotiator, and his battle with depression, watch SUNDAY, tomorrow at 7pm on TVONE.