A difference by serious crimes

in the middle of the night on my own,” he explained. “It was a double murder and that’s when I realised how lonely it can be when you are an SIO.

“I had locked someone up for killing his mam and dad. If I had got that wrong the persons responsible have run off into the sunset and I have got one of their victims in custody.

“It was my first significant job where I had the Chief Constable on the phone asking what was going on.”

But Det Chief Insp Fairlamb and his team had made the right call, and Ruddy was later convicted of murder and jailed for life with a minimum term of 35 years.

The detective said: “There’s no happy ending in cases like that in any shape or form.”

While probing the murders of Lee Irving and Jimmy Prout in 2014 and 2015, Det Chief Insp Fairlamb was faced with investigating horrifying levels of violence inflicted on vulnerable adults over a period of time.

“It does still shock you,” he said. “What they did to James Prout, you just can’t fathom it. You just can’t understand where these people come from.”

And Det Chief Insp Fairlamb says disabled Zahid Zaman, who, along with Ann Corbett was convicted of murdering Jimmy, is the most controlling criminal he has encountered.

“Zaman was probably once of the most controlling people I have ever seen,” he said. “He really pulled the strings of the others.”

The murder of 24-year-old Lee, who suffered from severe learning difficulties, was another example of a vulnerable adult being killed by those that controlled him.

He was befriended by James Wheatley who would go on to repeatedly assault him at a house in Newcastle, while his mum, girlfriend and their lodger were present.

Newcastle Crown Court heard how Lee was beaten and sedated with drugs, including morphine, to prevent him escaping his captors.

After he died, his body was wheeled in a pushchair and dumped near to the A1 in Fawdon.

“Lee didn’t have any friends so he stayed,” said Det Chief Insp Fairlamb. “It’s like aggravated bullying – and if it’s not stopped it will escalate.”

Police questioning passers-by at the Cascade furniture factory, Stoneygate Industrial Estate in Felling during the investigation into the murder of Stephen Sweeney The abandoned allotment shed in Fulwell, Sunderland, where serial killer Steven Grieveson killed Thomas Kelly, aged just 18