Alison Lewis, the lover of murdered mother Mandy Power, plans to sue South Wales Police for the "torture" she suffered when she was arrested over the four Clydach killings.

The former policewoman, who was held by her own force and questioned for four days, said she is vindicated by David Morris's conviction but wanted redress for the way she was "branded a murderer" by her detention.

South Wales Police has defended the way it handled the investigation, one of the largest murder inquiries in its history, which included more than 4,500 witnesses statements and 4,000 exhibits.

Paul Wood, the force's deputy chief constable, said detectives had acted on the evidence available to them at the time.

Mrs Lewis's husband, Stephen, and his twin brother, Stuart, both serving officers in the force, were also held in July 2000 and questioned over the murders, described in court as a "massacre"

Both men remain suspended from the force. Mrs Lewis has left the service and is now divorced from her husband.

Stephen Lewis has divorced Alison but is suspended from his job

At a press conference following Morris's conviction for all four murders, Mr Wood confirmed that South Wales Police had received notification from Alison Lewis that she intended to claim damages.

He said the process was at an early stage and he refused to comment further.

However, he added: "I have a great deal of sympathy for those people who have been caught up in this investigation, but I am sure people will understand that it is the duty of the police to follow the evidence at the time.

"That happens in many cases and that is what we have done."

Mrs Lewis read out a prepared statement on the steps of Swansea Crown Court immediately after the trial in which she showed her anger at the way the defence had portrayed her as the "probable" killer, as the police had originally suspected.

Inspector Stuart Lewis was the first officer at the murder scene

She said: "The judicial system afforded David Morris the luxury of being innocent until proven guilty.

"Throughout the trial, my rights as an innocent person were neither given nor respected as David Morris's defence team did their utmost to make me look guilty by implication and insinuation."

In all, Mrs Lewis was subjected to 23 police interviews by detectives.

She said: "I was interrogated. I was tortured with my grief for four long days.

"South Wales Police wrongly branded me a murderer, a murderer of the four people I loved.

"I feel I still need answers, and the only way for me to get those answers from South Wales Police is to sue them, because what happened on that day in July has effectively ruined my life."