SUZY Lamplugh murder suspect John Cannan has written a self-pitying letter from behind bars in which he taunts cops with chilling references to his bloody past.

The arrogant sex killer, behind bars for rape and murder of another woman, claims police are “assassinating” his character.

And he adds in the toadying note, seen by the Sunday Mirror and passed on to cops, that he feels “deeply upset” by an ongoing dig at his mum’s former home.

Cannan, 64, says that he even wanted to “throw myself off the building” after learning of the fresh police probe.

He writes: "At the time I was living my life very much in the shadows because of what I was doing, so take nothing at face value.

“Strange really, the reality of my life is so much more interesting yet it has been buried.”

Cannan has denied involvement in 25-year-old estate agent Suzy’s disappearance in 1986.

She vanished after leaving her office to show a property to a client known only as Mr Kipper in Fulham, South West London.

Cannan was let out of prison on day release just days before Suzy disappeared.

But his note, written from HMP Full Sutton, York, says he is "powerless" to defend himself.

He writes: “The police assassination of me has upset me deeply. Worse, I am in no position to reply to it so I feel powerless.”

Last week The Sun on Sunday revealed bombshell police interview tapes showing how Cannan was asked point blank “what have you done with her body”.

The 18 hours of VHS cassettes were found in a rubbish tip.

Their discovery in Sutton, South West London, came as police continued digging up the garden of his mother’s old house in Sutton Coldfield, West Mids.

At one point in the tapes Cannan confesses: “I have committed crime, I have done many things wrong in my life, things that believe me I am genuinely sorry for, one or two things I haven’t even been caught for.’’

Another time vain Cannan asks for a comb, saying as he stands in front a mirror straightening his hair: “I must look terrible.”

Clearly marked with the name John Cannan, the videos date from the Met’s Operation Phoebus — a re-investigation of the Lamplugh case in 2000.

They were handed to The Sun on Sunday by a concerned member of the public.

The fact the tapes were seemingly dumped raises further questions about parts of the police probe.

Earlier The Sun revealed lead detective Malcolm Hackett fell out with Suzy’s campaigning mum Diana because he believed she was behind media reports linking Cannan to Suzy.

The detective superintendent so resented her demands to question Cannan that he failed to interview him properly, put him in ID line-ups or check his alibi for the day Suzy vanished.

Retired Det Supt Jim Dickie, who led Operation Phoebus, said of the tapes: “I find it incredible they have been found in this way.

“There has obviously been a serious security breach.”

Mr Dickie devised the interview strategy and watched the grillings from an adjoining room on TV.

Former car salesman Cannan had been given three life sentences with a recommendation he never be released for the murder of Shirley Banks in Bristol, in October 1987.

He was also jailed for the attempted kidnap of Julia Holman the previous night and the rape of a woman in Reading a year earlier.

He is also a suspect in killing of Bournemouth insurance clerk Sandra Court.

He was questioned over three days in December 2000 at Hammersmith police station in West London after transferring from Full Sutton jail in Yorkshire.

Further interviews were later carried out at a Yorkshire police station.

Mr Dickie said Cannan behaved “like his usual arrogant self”.

He said: “He had put on a lot of weight by then and his body language was very arrogant to begin with.

“He tried to take over the interviews. Our strategy was to let him talk and say his bit to begin with. But his whole demeanour changed as we started to put the evidence to him and he began to look uncomfortable.

“He didn’t really answer the questions and he looked like he wished he was somewhere else. He tried to move the interviews off at a tangent.

“It was eventually put to him he had murdered Suzy and he was asked what he did with her body. No explanation was forthcoming.”

Privately educated Cannan first told detectives: “I don’t really see, as things currently stand what else there is to be said. Mrs Lamplugh thinks I’ve done it.

"I’ve invited Mrs Lamplugh to come to Frankland Prison to question me.

"I’ve said I will take a lie detector test, the truth drug. I will go on anything anyone wants me to do.”

He tells Det Chief Insp Stuart Ault: “Mrs Lamplugh believes I have killed her daughter. I haven’t.”

At one point he is offered water and jokes: “Is there anything to go with it?”

As the questioning continues, Mr Ault tells Cannan: “This is all about the tracing, elimination of suspects . . . and I want to talk to you about ambiguities in three interviews you gave in 1988, 89, and 90.

“New evidence has also come to light as part of that review and that’s why you are here.”

Cannan is told that three copies of the tapes will be made and one will be made available for him and his legal team.

Cannon politely tells officers he does not want to speak to them, moans about his treatment and claims cops had been leaking details of previous investigations.

Visibly losing his temper for the first time, Cannan raises his voice as he tells DCI Ault: “Sir, I don’t trust you. I think you are duplicitous.

“I’m not saying you are, I am not saying you personally, I think something is going on that is wrong.”

When Mr Ault interrupts, Cannan fires back: “Let me finish, I haven't quite finished sir, not quite. You are not involved in a prosecution, you are involved in a persecution.”

After Operation Phoebus ended, the Crown Prosecution Service decided there was insufficient evidence to charge Cannan.

But in November 2002 the Met took the unusual step of naming him as their prime suspect for Suzy’s murder.

She vanished on 28 July 1986 after going to meet a client named Mr Kipper to show him two properties in Fulham, South West London.