A man convicted of assaulting his ex-partner was found dead with her the day after being bailed by police, despite allegedly breaking conditions.
Lee Guntrip, 25, was told not to enter Sarah Nash's road or contact her under the terms of his release after he was arrested for offences against her.
Two days later he was alleged to have breached these, but was still released on bail again by police.
The next day both were found dead in Berkhamsted, Hertfordshire.
Hertfordshire Police has not confirmed if it is treating the case as a murder-suicide.
The case was referred by the force to the Independent Office for Police Complaints (IOPC), which has now given them seven recommendations to follow.
In January 2016, Mr Guntrip admitted causing actual bodily harm and assault by beating.
St Albans Crown Court heard he had grabbed Ms Nash's throat and banged her head against a cupboard, while on another occasion he had grabbed her by the wrists.
He was sentenced to a two-year community order and told to attend a relationship course.
Following his conviction, Mr Guntrip was later arrested for offences against Ms Nash, who was 37 and a mother-of-two.
He was bailed with conditions not to enter his ex-partner's road or contact her directly or indirectly.
Two days later, he was alleged to have done both, but was still re-bailed by the investigating officer on 29 June 2016.
Ms Nash and Mr Guntrip were discovered dead in her home in Highfield Road the next day.
Hertfordshire Police has accepted six of the IOPC's recommendations.
They include ensuring all staff investigating domestic abuse have access to relevant systems and that an officer in charge of a domestic abuse investigation is "sufficiently qualified and suitable for the role".