The way parole is considered is to be reviewed following the decision to release serial sex attacker John Worboys, the prime minister has said.
Theresa May said she was determined to do "what is necessary" to bring "greater openness" to the decision-making process of the Parole Board.
Victims of black-cab rapist John Worboys feel "betrayed" by the decision to release him, a solicitor has said.
The PM also revealed that she knew one of Worboys' victims.
Speaking on the Andrew Marr Show, she explained that the victim she knew had not been told that he would be released, but had heard about it through the media.
"I fully recognise why people are concerned about this", she said.
"We want to ensure that victims feel confident enough to come forward, so that they feel confident that the police will take action, and confident that they will get justice."
In a statement, the justice secretary, David Lidington, acknowledged that Worboys' release "must have reawakened the most appalling memories".
He said there was a "strong case" to review the system in order to make sure that victims had the option to be kept informed about cases.
Worboys, who was convicted of 19 offences and is suspected of attacking more than 100 women, has served ten years in jail.
When sentenced, he was given an indeterminate sentence of imprisonment for public protection (IPP) and told he would not be released until parole officials were convinced he did not pose a threat to women.
After a hearing about his case in November, the Parole Board decided to approve his release with "stringent" licence conditions.