The man who murdered a 26-year-old woman before dumping her body in Taplow Lake in 1987 has been locked up for decades. 

Donald Robertson, formerly of Slough, was jailed after being unanimously convicted of kidnapping, indecently assaulting and murdering Shani Warren at Reading Crown Court earlier this week. 

The 66-year-old was also sentenced for the kidnap and rape of a Slough girl, aged 16 in July 1981. 

He was finally brought to justice more than 35 years after Shani Warren was discovered tied up and gagged in Taplow Lake on April 18, 1987. 

A pathologist initially concluded Ms Warren had killed herself following examination of her body after her discovery. 

But the case was re-opened in 2018 after the mouth gag found tied around Ms Warren’s head was re-tested using advanced DNA technology. 

Slough Observer:

Results showed DNA matching the profile of Donald Robertson on the gag. 

Following his arrest in the summer of 2021, Robertson was charged with Ms Warren’s murder in November of that year.

He was also charged with the rape of a 16-year-old girl in July 1981. 

Robertson was tried on both these matters at the start of April but declined to attend for any of the hearings during the three-week trial.  

During the trial, Reading Crown Court heard how Robertson had previous convictions for the rape of a 14-year-old girl in August 1981 and a 17-year-old girl in July 1987 -- the latter offence coming just months after the murder of Shani Warren. 

He also had convictions for raping a 15-year-old girl in 1977 and sexually assaulting an 11-year-old girl at a fairground in London in 1997. 

The Slough man was only free for four of these 20 years, Reading Crown Court heard. 

Robertson opted not to show up for his sentencing after a jury found him guilty on all five counts levelled against him. 

Mr Justice Wall, sentencing, addressed Robertson’s rape of the 16-year-old girl first. 

The court heard how Robertson jumped out in front of the girl near Britwell Estate in Slough and made her strip before having sex with her against her will. 

Robertson told the girl he would kill her if she told anyone what he had done. 

Mr Justice Wall said: “it was only 41 years later that you were convicted of these crimes and she could feel secure in the knowledge that her assailant had finally been caught. 

“Her impact statement, which I have read with care, makes it clear that the horror of that evening has haunted her throughout that time.

“You have blighted much of that lady's life for a few moments of pleasure.”

Moving to the murder of Shani Warren, Mr Justice Wall said it remained unclear exactly what happened 35 years ago.

He added: “I have no doubt that you sexually assaulted her [...] and then forced her into an act of oral sex. 

“At some stage, you attempted to strangle her using a car jump lead as a ligature. 

“At some stage you bound and gagged her and threw her into the water of Taplow Lake.

“She was likely to have lost consciousness [before going into the lake]. 

“That explains why she was not able to shake off the shackles when she was in the water.”

The judge said he could not be sure why Robertson killed Ms Warren when he did not kill his other rape victims. 

“I am sure that when you threw her into the lake you intended that she should die. There is no other plausible reason for binding and gagging her before throwing her unconscious body into that water.

“In her case, her family had to wait 35 years before they could know with certainty that you were responsible. 

“They have been told at times she probably killed herself, and at others she might have been killed by another man [...]

“The suffering of losing someone aged only 25 (as she was) in such brutal circumstances is unimaginable to those who have not gone through it. 

“The extra anguish of having to wait so long for the truth surrounding her death to emerge must make that suffering even harder to endure. 

“Her parents have both recently died and never got to find out that the killer of their daughter had been identified and successfully prosecuted for murder.”

Robertson was handed a life sentence to serve a minimum of 30 years for murder, two counts of kidnap, indecent assault and rape at Reading Crown Court on Thursday, May 19.

However, should he still be alive, he will only be released with permission from a parole board.