Three men have been arrested in connection with the unsolved rape and murder of a young woman in Belfast 30 years ago. The Police Service of Northern Ireland said on Wednesday it had detained the trio as part of a fresh investigation into the sexual assault and killing of Lorraine McCausland.

The 23-year-old, who had two young children, was found beaten to death in a stream in north Belfast. She had been last seen at a loyalist paramilitary drinking club.

No one has been convicted over the murder, carried out in March 1987, but sources said her attacker was a senior member of the Ulster Defence Association (UDA), the group that controlled the drinking den.

The woman’s son, Craig McCausland, who was two when she was killed, was shot dead in 2005 by another loyalist terror group, the Ulster Volunteer Force.

A PSNI spokesman said on Wednesday that two men aged 49 and 56 were arrested in Scotland, while a 53-year-old man was detained in England. All three will be taken to Northern Ireland where they will be questioned by detectives over the 1987 McCausland murder.

Michelle Griffin, a detective inspector, appealed for anyone with information to contact the non-emergency phone number 101 or the independent charity Crimestoppers anonymously on 0800 555 111.

One of the allegations surrounding Lorraine McCausland’s murder was that her killer was a police informer working inside the UDA who might have been protected by the state.

The historical enquiries team, which investigates unsolved murders and other crimes that took place during the Northern Ireland Troubles, concluded that the chief suspect was an informer for the RUC special branch. However, the team said they could not prove there was any collusion between the suspect and his police handlers.

The Northern Ireland police ombudsman’s office is also investigating claims about serious police failings in bringing the suspect to justice.

At the time of the rape and murder the UDA in the Tyndale and Upper Shankill area of Belfast imposed a code of omertà on those who were inside the club where McCausland was last seen. None of the 20 people there at the time said they had seen anything suspicious regarding McCausland or any of the men police later identified as suspects.

McCausland’s father took out an advertisement in the Belfast Telegraph offering £1,000 for information after her death. It read: “Someone knows – please help.”

The PSNI said the latest arrests were a result of a cold case review that had identified potential new lines of inquiry for the reopening of the rape and murder investigation. In the original investigation 14 arrests were made but no one was charged.

After the revelations in 2014 that the chief suspect was an informer, Lorraine’s sister Cathy McIlvenny said: “It’s hard knowing who was responsible and being able to do nothing about it. They didn’t just murder Lorraine, they destroyed a family, her two boys, her brothers and sisters. It changed life completely.”

Craig McCausland was shot dead by the UVF in front of his girlfriend at the height of a murderous feud between the group and the rival Loyalist Volunteer Force. His family and loved ones claimed he was the victim of mistaken identity who had been wrongly targeted as a member of the LVF.