Suzy Lamplugh police missed key chance to catch prime suspect days after she went missing

John Cannan, who has died in prison aged 70, was not treated as suspect in Suzy Lamplugh's disappearance for six years despite being convicted of another murder and a string of sex attacks

Police missed a chance to catch the prime suspect in the murder of Suzy Lamplugh, a former detective has revealed.

John Cannan has died in prison aged 70 without disclosing what happened to the estate agent 38 years ago. Suzy, 25, went missing in July 1986 after going to meet "Mr Kipper", according to her diary, to show him a house in Fulham, West London.

Cannan was identified in the original investigation as a person of interest because he had recently been released from a hostel at Wormwood Scrubs, where he'd served a sentence for rape. But he was not spoken to by detectives until he was jailed for life in 1989 for the rape and murder of newlywed Shirley Banks, along with further sex offences and kidnapping. And even at that point, police did not arrest or caution Cannan, only questioning the monster as a witness and not a suspect.

Ex-detective superintendent Jim Dickie, who led a cold case probe that finally arrested Cannan in 2000, said: "He was in the system but for some unknown reason he was only treated as a witness who would help the inquiry. For me it's unbelievable. He was a convicted serial sex offender who had just been released from prison when Suzy disappeared." In 2002, police took the unusual step of naming Cannan as the only suspect in Suzy's murder after the CPS ruled there was insufficient evidence to prosecute him.

Mr Dickie said it was impossible to say if the case would have been solved if detectives had arrested Cannan earlier. He said criminal profiling experts found Cannan had the "opportunity and propensity to commit this type of crime in broad daylight". The day before Suzy disappeared, a witness saw a man they picked out as Cannan peering into the estate agent's window. Mr Dickie said he was the only suspect in the investigation after his team were able to discount seven other men.

Cannan was later jailed for the rape and murder of Shirley and a series of other attacks including attempted kidnapping and sexually-motivated abductions. He died while an inmate at Full Sutton jail near Pocklington, East Yorks. The Prison Service said: "John Cannan died on 6 November. As with all deaths in custody, the Prisons and Probation Ombudsman will investigate." Police carried out excavations in Sutton Coldfield, Birmingham, in 2018 at the former home of Cannan's mum, but nothing was discovered.

Cannan wrote to the Mirror from jail last year insisting he did not kill Suzy. He said detectives had pointed the finger at him to divert attention away from themselves. He said: "I was not involved in the disappearance of Suzy Lamplugh. I have an alibi." Cannan claimed that on the day Suzy vanished, he had been in Birmingham having lunch with his mum. Mr Dickie said he interviewed Cannan's mother and she could not confirm this while the suspect was unable to provide any evidence to back up his alibi.

Shirley, 29, of Bristol, was abducted in 1987 while on a shopping trip. Her body was found in a stream six months later.