A television recruitment consultant died after being stabbed 57 times by her boyfriend.
Amina Adan, 32, suffered a year of domestic violence after meeting Zakaria Mohamed, 29.
While on bail for assaulting her, Mohamed killed her at her home in Walworth, south London, after persuading her to take him back.
After his drunken rage at Miss Adan, who worked for Al Jazeera television, Mohamed refused to put his knife down.
The unemployed Somalian was arrested by police after he was Tasered by officers last November.
Mohamed, of Alberta Street, Peckham, south London, pleaded guilty to murder today, changing his plea as his trial was due to begin.
He was remanded in custody at the Old Bailey for sentencing on Friday.
Timothy Cray, prosecuting, told the court: "The murder arises out of a background of domestic violence on the lady who died by this defendant."Suggest a correction