THE actions of officers who missed chances to catch a double killer are being investigated by two other police forces.

In July it emerged the police watchdog would not be investigating how the deaths of Susan Nicholson and Caroline Devlin were handled.

Sussex Police initially said the deaths were not suspicious but in July Robert Trigg, who had been in a relationship with each of the women at the time they died in 2006 and 2011 in Worthing, was found guilty of Ms Nicholson’s murder and the manslaughter of Ms Devlin and jailed for life.

Instead the force said it would carry out a fourth internal review.

The news came as The Argus revealed the force stood by its decision not to prosecute Trigg in three internal investigations which found nothing wrong with its handling of Ms Nicholson’s death, despite fears she had been murdered.

Later that day Assistant Chief Constable Laurence Taylor announced the force would carry out another internal review into its original investigations into both women’s deaths.

He said they would be “robust and probing”, the force would act on key findings and they would be published.

But concerns were raised over the news the force would be investigating itself again.

Yesterday, Sussex Police told The Argus two other police forces would now be leading the reviews and these would be independent.

A spokesman would not confirm yesterday which forces are carrying out the reviews but said this would be announced in due course.

The first police probe is anticipated to be completed within a matter of weeks.

A separate police force will then look at how officers handled complaints made by Ms Nicholson’s family about the case.

Asst Ch Con Taylor also asked West Sussex County Council to carry out an independent review into how all public bodies were involved in the deaths.

Yesterday, The Argus also learned the council has since asked the Safer West Sussex Partnership to carry out the inquiry instead.

This will be made up of a panel of representatives of public bodies including the police, health professionals and local authorities. More details are expected soon.

Ms Nicholson’s father, Peter Skelton, 82, of Goring, said: “We are pleased to hear about the reviews and think it’s very important and much better they are going to be independent.

“It was not right they investigated themselves again. We still have so many unanswered questions so we hope these investigations will provide the answers we need.”

His wife Elizabeth, 81, said Chief Constable Giles York has made a personal apology and they have been invited to claim compensation.

In July after Robert Trigg was sentenced to life behind bars police apologised for the way they handled the investigations initially.

Assistant chief constable Laurence Taylor previously said he was "truly sorry" it had taken so long for the family to get justice.

He added: "We do take these matters seriously, we do listen and we constantly strive to be the best we can be."

Mrs Skelton said at the time: "We have just been ordinary people asking ordinary questions.

If the jury could convict Trigg in six hours, why could the police not see there was a problem?"