A convicted killer had threatened to attack and rape a woman around a month before going on to murder a "beautiful" Vietnamese mother-of-two, an inquest has heard.
Nail technician Quyen Ngoc Nguyen was murdered by Stephen Unwin and William McFall on August 15 2017 before being dumped in her own car and set alight on Shiney Row, near Sunderland.
The pair, who were both convicted of the 28-year-old's murder and sentenced to full-life terms in April last year, had both previously separately committed murders and met while in prison for those offences.
They had met their victim whilst working as handymen on several flats that she was renting out, their trial at Newcastle Crown Court heard.
An inquest into the death of Ms Ngoc Nguyen started on Tuesday at Sunderland Coroners' Court after coroner Derek Winter decided it was necessary to look into whether the police and probation service missed opportunities to prevent the murder.
The court heard how Unwin, of Houghton-le-Spring, Sunderland, was released from jail on licence on December 20 2012, with Northumbria Police receiving 26 "items of intelligence" between his release date and the murder of Ms Ngoc Nguyen.
Detective Inspector Edward Small told the court that one of those items related to a complaint from a woman that, on July 2 2017, Unwin had sent her a Facebook message threatening to "smash her jaw in" and take turns with an accomplice to rape her.
The court heard how the complainant in that incident had mentioned to officers that Unwin had served prison time for murder, but Mr Small said she had not chosen to take the incident any further.
Another item of intelligence related to a report that Unwin had allegedly threatened to assault a teenager, the inquest heard.
The witness explained how changes made by Northumbria Police meant that "flags" - meaning relevant intelligence - that appeared on the record of prisoners released on licence would no longer be passed on automatically to the relevant authorities, including the probation service.
Mr Small said that, from April 24 2015, a change to the force's system meant that officers would have to pass on these flags to authorities themselves by their own discretion, in a bid to reduce workload.
But he said that a "warning" would remain permanently on the records of people like Unwin and McFall, showing that they were out of jail on licence.
The witness also said that, after looking into the circumstances of Ms Ngoc Nguyen's death, Northumbria Police introduced a system whereby flags are passed on to a "multi-agency safeguarding team" in December last year.
Outlining the case, the coroner said that it appeared the probation service had contemporaneously updated their record of Unwin until December 13 2016, adding that the next record of contact was made on August 18 2017 - three days after the murder.
Discussing the scope of the inquest, Mr Winter said he would consider whether the killers' level of risk was properly assessed and whether information relevant to a "potential recall" of the men prior to Ms Ngoc Nguyen's death was brought to the attention of the relevant parties.
In a statement that was read at the start of the inquest, the victim's sister, Quynh Ngoc Nguyen, said: "My late sister was a very kind, beautiful girl, a great daughter and a caring mother with a warm heart."
She said that the victim's son often asks if she can "bring him to heaven" so that he can be reunited with his mother.
The sister added: "Our family is indignant at the actions these two terrible men brought to Quyen."