A couple have been jailed for life for the murder of a homeless woman they drowned in their bath before claiming her benefits.

Kevin Flanagan was told by a judge on Friday he must serve a minimum of 32 years in prison for killing Lisa Bennett, while his girlfriend, Kathleen Salmond, was given a minimum term of 27 years.

The pair had conspired to drown the vulnerable 39-year-old before dumping her body in a communal bin. Her remains have never been recovered and it is thought the body was incinerated at a waste facility.

Kevin Flanagan outside court. Photograph: Steve Parsons/PA

The couple then received £4,979 after fraudulently claiming Bennett’s benefit payments while pretending their victim was still alive.

Kathleen Salmond covers her face outside court. Photograph: Matthew Cooper/PA

The crime was uncovered when Flanagan’s brother told the police his sibling had confessed to the killing after he saw a missing persons appeal led by the victim’s mother in 2014.

Flanagan, 39, of Kings Norton in Birmingham, and Salmond, 40, of Hodge Hill in Birmingham, were convicted of murder on Wednesday after a trial at the city’s crown court.

Salmond, who appeared during proceedings via videolink from a bed, was also found guilty of benefit fraud between 8 and 31 May 2013 and preventing Bennett’s burial – charges Flanagan previously admitted.

Opening the case, the prosecuting barrister, Simon Denison QC, told jurors how the victim was told she would be eating her “last dinner” before she was killed.

Flanagan and Salmond, who uses a wheelchair, carried out the killing in their flat in Weoley Castle in Birmingham on or around 9 May 2013.

The jury heard how the defendants “reaped the benefit of Lisa’s disappearance” after Salmond phoned the Department for Work and Pensions, pretending to be Bennett, and arranging for £230 benefit to be paid into her own account.

Flanagan also used the victim’s phone to text her mother “to make her believe that nothing had happened and Lisa was alive”, prosecutors said.

When questioned over the disappearance, the couple told police Bennett was “alive and well” and that she had asked them to transfer her benefits into Salmond’s account.

The pair also claimed a fictitious boyfriend of Bennett’s, named “Ian”, was collecting the cash each week.

Jurors were told Bennett, who was addicted to drugs and alcohol, was last seen collecting a prescribed heroin substitute from a pharmacy.

Under cross-examination from Salmond’s barrister, Flanagan said he told his brother Bennett “died from an overdose”.

Flanagan, who had numerous convictions going back more than 20 years for theft, robbery and shoplifting, did not react as he was convicted.

Salmond, who had a criminal history stretching to 2010 with convictions for assault and battery, also appeared not to move in her bed as the verdicts were read.

Speaking afterwards, David Parsons, for the Crown Prosecution Service, said: “Kevin Flanagan and Kathleen Salmond have received lengthy jail sentences for the brutal and senseless murder of a vulnerable woman. Flanagan will be 71 years and Salmond will be 67 years before they can be considered for release.

“They befriended Lisa Bennett and then callously cut her life short causing immeasurable pain for those who loved her. Lisa’s parents were deprived of the opportunity to bury their daughter and say goodbye.

“Today, they have received life sentences for their crimes and while this can never bring Lisa back, I hope today’s sentencing brings some small comfort to Lisa’s parents, who have suffered immensely due to Flanagan and Salmond’s cruelty.”

• This article was amended on 14 December 2019 to correct the surname of Kathleen Salmond in the subheading.