My Father In Law’s Deathbed confession – what can I do to help?

TL;DR: My father in law (FIL) passed away recently. I visited him a few days before he died and he confessed to knowing where some bodies are buried and wanted me to help make it right.

Going back to the beginning: It was the mid 1970s and he was a young man struggling with work. He’d just trained as a digger/excavator operator and was trying to break into the construction industry but in the part of the country he lived in, it was more about who you knew rather than what you knew.

He’d applied to several different building firms for work but was getting nowhere, until one day, he received a phone call telling him to come to a construction site of a housing estate that was being built by a large British housing construction company. Relieved, he arrived early and was a very dedicated employee. For the next few months, he was praised and treated better than he’d ever been treated either at work or at home. The boss took him under his wing, taught him a lot about the trade and they developed a friendship.

One Saturday afternoon, his boss calls him. He tells him that he’s needed on site later that night and there were to be no questions asked. His boss also told him that after that night, he would invest in him and buy him a (used) digger so he could start his own company and rent himself and his digger to different building sites. This meant he could start his business, which is still ruining today and is now run by my brother-in-law.

He turned up to the site and was told to dig a trench of a specific size. When he had dug the trench, he waited for a short amount of time until people living on the completed part of the estate came out of a house across the road from this plot carrying black bags with something heavy in them. They were put in the trench and he was instructed to cover it back up again, which he did. FIL swears that they were dead bodies. Several of them.

When he tried to talk to his boss (who was also there), the boss reminded him of the no-questions and told him he would be getting his digger in a matter of days. He told him to never discuss this again and made some veiled threats. Within a short time he had his digger and built up his business over the years. He noted that that part of the housing estate was not being built on, but had tarmac laid on it. Eventually he moved to a different part of the country where there was more work, met my mother-in-law and moved on with his life and business.

He told me that the events of that night always played on his mind and was always at the back of his mind. He knew that he'd taken the digger as a hush payment and was afraid of his old boss.

Years later, shortly after I had married my wife, I showed him a new website: Google Street View. He was amazed by it. He told me that after I had left that day, he looked up that street on Google street view. The estate he had worked on was still standing. The plot he had dug a trench into had been left empty and still had tarmac laid on it. It wasn’t a park or a green-space, just a plot of tarmac. He told me the address and I was able to find it on Street View and the empty plot of tarmac is still there.

When I left, my mother-in-law (MIL) was at home, visiting my wife. She gave me a ring binder that FIL had kept. It was full of information about that estate, with land registry records, newspaper stories, housing sale information. There were also some missing persons stories from around the country from the same time, which were mainly kids. What was interesting were the numerous print-outs from local newspapers and from the planning department regarding that patch of land. The construction company that built that estate no longer existed and that plot of land had been purchased by a private developer. The developer had tried for years to build a house on that plot of land (as it was now a costly housing estate in a popular town). The developer had been stopped by the efforts of the people who lived directly opposite. I saw on the land registry that the house had stayed with the same owners since the mid 1970s and, as shown in local newspaper website printouts, they had called upon MPs, the planning department and even my FIL’s old boss (who became a local councillor). The last time there was an attempt to build on that land was 6 years ago. They had got it rejected on the grounds that it would destroy green-space, which was odd, because there was no green-space to be destroyed. It was just a patch of tarmac, now with some shoddy looking benches on it (to make it look more like a park, I suppose).

My FIL was convinced that they murdered several people, got away with it, and are still guarding the site where the bodies are buried. He tried to contact the police one one occasion, shortly after he was acquainted with street view. He left his phone number only to be called back by a councillor, who happened to be his old boss. This terrified my FIL. He believed his old boss was involved with organised crime and said that was part of the reason he moved to a different part of the country.

He asked me to help make it right. I’ve already tried calling the local police and was told in no uncertain terms to 'fuck off' and 'stop wasting police time'. I’m not sure what to do. I don’t want to endanger myself and my family but I want to help FIL with his last wish. He was absolutely convinced that there were bodies buried there and the evidence in the amount of effort gone into protecting that plot of land seems to suggest he might be on to something.

Any ideas?