Murder or medical mix-up? New questions in the case of killer nurse Colin Norris

Image source, PA Media Image caption, Colin Norris has been in prison for 18 years

For two decades, Ethel Hall's family believed that staff nurse Colin Norris murdered the 86-year-old by injecting her with insulin while she recovered from a broken hip in a Leeds hospital.

After his latest appeal against conviction, some members of Ethel's family are having doubts.

"The evidence, it's just not sitting right to me," daughter-in-law Helen Hall told a new BBC podcast, Disclosure Investigates: Killer on the Ward .

Norris was convicted in 2008 of killing Ethel and three other elderly patients as well as attempting to murder a fifth.

The Court of Appeal rejected his challenge against his convictions last year but the new BBC podcast has reviewed medical records, looked again at police interviews and heard about new scientific discoveries.