Phillip Nicholson was killed in a Boscombe flat in 2015

The hearing, which will be held behind closed doors next month, will look at police contact with Phillip Nicholson ahead of his killing by his ex-girlfriend and her new partner.

Mr Nicholson was lured to a flat in Sea Road, Boscombe on May 26 2015 by Isabella Gossling and Richard Moors. The two then murdered him in a 17-minute attack which was recorded on Gossling's phone.

The officers have been the subject of an investigation by the Independent Office for Police Conduct (IOPC).

They were initially served with gross misconduct notices. However, they now face allegations of misconduct.

Gossling was convicted of murder following a trial at Winchester Crown Court in 2015. Moors admitted murder at an earlier hearing.

Both were sentenced to life in prison.

During the trial, it was heard that police had been called in as a result of concerns about the relationship between Mr Nicholson and Gossling around 18 months before Mr Nicholson's death.

Mr Nicholson had been assessed as being at very high risk of sexual, mental, financial and emotional abuse by an independent domestic violence advisor.

He had an IQ of 62 and lived in assisted accommodation in Parkstone.

A threat was made against the victim 11 days before he was stabbed to death, it was heard.

Misconduct notices do not imply guilt but are to inform the officer that their behaviour and conduct are under investigation and the level of severity.

Dorset coroner Rachael Griffin held a pre-inquest review into Mr Nicholson's death last Friday. During the hearing, Mark Ley-Morgan, counsel for Dorset Police, said the three officers will face a hearing in May.

"Mr Nicholson's family will be able to attend that meeting, but members of the public will not," he said.

"On behalf of the police, I'd like to say changes have been made since Mr Nicholson's tragic death.

"I think [Mrs Griffin] will want to hear from somebody [in the force] about what has happened since, what lessons have been learned."