Bob Spiers, a well-known officer in Garstang, collapsed in the town centre where he had spent so many years as a beat bobby.
Paramedics and police fought to revive him, but were unable to save his life.
Son Scott said: "Dad is going to be missed by a lot of people. He was so well-known and well-liked in the area.
"He was the ideal beat bobby because he loved people and loved meeting and talking to people. He loved going into town shopping during the week.
"In recent years, as one of the last remaining officers who worked on the Moors Murders inquiry, he was regularly asked to do interviews by newspapers and TV."
Bob had only been a police officer for a month when he found the first body on Saddleworth Moor in October 1965, that of 10-year-old Lesley Ann Downey.
In an interview with the Lancashire Post in 2015 - the 50th anniversary of his grim discovery - he told how the police search on the moors was being wound up after two unsuccessful days when he decided to have one last look.
His persistence paid off when he noticed what he thought was a stick poking out of a water-filled hollow. It turned out to be Lesley Ann Downey's arm.
"I said I've found something, but nobody wanted to know," he recalled. "The DS said it was probably a sheep. I said: 'If that's a sheep it's wearing clothes."
Had Bob not taken one last look at the site then the full extent of Brady and Hindley's horrific crimes may never have been unearthed and the pair may only have been charged with one murder - that of 17-year-old Edward Evans - and may not have served the rest of their lives behind bars.
Further searches of the moors discovered the bodies of Pauline Reade, 16, and John Kilbride, but the remains of 12-year-old Keith Bennett have never been found.