Devastating

He said: “Those convicted of the murder of her children now need to be charged with her murder.

“Time is no longer a bar to prosecution. Such a sad case.”

Detective Superintendent Lewis Hughes said: “As the senior investigating officer, I know how devastating the death of her four children was for Michelle and the news of her passing is incredibly tragic.

“I would like to extend my sincere condolences to Michelle’s loved ones at this terrible time.”

The Pearson home went up in flames after petrol bombs were thrown into their house at around 5am on December 11, 2017.

Michelle’s son Kyle managed to escape, with his mother and young sister Lacie pulled from the flames. The toddler died two days later.

Bolland, 23, was convicted of four counts of murder and three of attempted murder. He was given a minimum 40-year sentence at Manchester Crown Court. His friend David Worrall, 26, was also convicted of the four murders and three counts of attempted GBH and given a 37-year sentence.

Bolland’s girlfriend Courtney Brierley, 21, was found guilty of four counts of manslaughter and jailed for 21 years. She recently lost an appeal against the length of her sentence.

Ms Pearson was left too ill attend her children’s funerals to in September 2018. Earlier this year the family shared a video of her in a wheelchair with a tracheotomy tube releasing four balloons in memory of her four children.

Bolland and Worrall filled a petrol can at a garage. They smashed a kitchen window at the home and tossed in two petrol bombs.

One landed near the stairs, blocking the only exit and trapping the occupants who were asleep.