The mother of a Spanish woman who died by euthanasia following a gang-rape ordeal has launched a bid to track down the men who allegedly carried out the attack - after uncovering new details in her late daughter's diary.

Noelia Castillo Ramos became paraplegic after jumping from a roof in the aftermath of the alleged assault, before choosing to end her life through Spain's assisted dying law.

She died aged 25 on March 26 at the Sant Pere de Ribes assisted living facility in Barcelona.

On Thursday, her mother, Yolanda Ramos, announced that she had filed two complaints with the public prosecutor's offices in Barcelona and Tarragona to demand an investigation into the alleged sexual assaults her daughter suffered.

Ramos, represented by the Spanish Foundation of Christian Lawyers, seeks to identify the alleged assailants based on evidence from Noelia's diary, which the young woman gave to her on the day she died.