Campaigners are urging Justice Secretary Dominic Raab to prevent the early release of British Airways captain Robert Brown, who was sentenced to 26 years for the manslaughter of his wife Joanna Brown in 2010.
Among the campaigners is Dianna Parkes, the victim's mother, and Carrie Johnson, one of the victims of serial rapist John Worboys, who joined the launch of the campaign on Wednesday.
Brown is due to be released on licence later this year after serving half of his sentence.
In 2010, Robert Brown killed his wife Joanna Brown with a claw hammer in their family home in Windsor, as their two young children cowered in a playroom.
Brown pleaded guilty to the charge of manslaughter on the grounds of diminished responsibility and received a 26-year sentence.
Dianna Parkes and Carrie Johnson spoke out about their experiences at the launch of the campaign to prevent Brown's release.
While Johnson spoke of her own fear about the release of John Worboys, who was jailed indefinitely in 2009 for rape, Parkes said her daughter's death was a "life-changing tragedy.
" Johnson attended the event with former prime minister Boris Johnson, former justice secretary Robert Buckland, former home secretary Priti Patel, and shadow minister for domestic violence Jess Phillips.
The campaigners called on the justice secretary to intervene and block Brown's automatic release from prison.
According to The Guardian, at the event, Johnson said she was "horrified" by Simpson's story when she was approached by her friends and family at an event organised by the queen consort at Buckingham Palace last year.
The Independent reported that Johnson recalled her fear over the planned release of serial rapist John Worboys.
The BBC News focused on Parkes' campaign to prevent Brown's early release, stating that she called her daughter's death a "life-changing tragedy."