We spoke to Bob Bridgestock, half of bestselling husband-and-wife crime-writing team RC Bridgestock and a career detective of 30 years with the West Yorkshire Police. The former Detective Superintendent dealt with dozens of murders and suspicious deaths - and one of his few unsolved cases involves a victim who was shot in a garage. Here’s what he had to say - it’s worth noting that he hasn’t seen the series.

Some viewers thought Brendan Dassey was more innocent than he suggested after police interrogation. Do innocent people confess?

Sadly they do, or should I say they used to [in the UK], prior to the introduction of the Police & Criminal Evidence Act 1984, which brought in the required recording of interviews and the need for a suspect to have legal representation.

There was a similar case in West Yorkshire in 1975. Stefan Kisko was arrested and convicted for the abduction and murder of an 11-year-old girl, Lesley Molseed. He confessed and served 16 years in prison, until developments in forensic science showed that it couldn’t possibly be him.

In 1992, when he was 40, he was freed on appeal and died a year later of a heart attack. There had been a long campaign by family suggesting he was innocent.

The three senior officers and a forensic man were charged with suppressing evidence but this was never pursued because the lead detective died. The suggestion was that the detectives had bullied a confession out of him.

Even when Kisko was released the detectives insisted he must have been there, and he must have had an accomplice.

These days admissions alone would not be sufficient to convict anyone of a crime. There is a need for other irrefutable evidence, such as DNA or fingerprints.

Both Brendan and Steven have very low IQs. How is a suspect’s IQ considered in questioning?