Both murders took place during the winter in Värnamo, 170km south-east of Gothenburg. In the first killing, a woman was found dead in December, having been strangled with a piece of wire.

The woman’s mother was killed in February. The murderer had killed her using plastic bags and a dog leash, which she used to strangle her.

The accused woman denies both murders and told police she cannot explain why her mother died. During questioning she repeatedly told police that she was not her mother’s murderer, according to documents released by Jönköping District Court on Wednesday.

“My mother was my security in life,” the woman told police.

The accused woman was found in a ‘poor state’ following the discovery of the mother’s murder. She fell asleep twice during her first interrogation. She told police that she found her mother sitting on the toilet. She later told them that her mother was tied up and gave other details, but was unable to give an explanation of the circumstances of the death.

The other murder had originally been classified as suicide, but the case was reopened when police noticed similarities with the other death. However, the original post-mortem investigation discovered no indication that the death was suspicious.

The motive for the first killing is unclear, but police say that the suspect used to ask the dead woman to sell her prescription drugs, something that made her feel threatened.

It is rare for a woman to murder two other women. To try to disguise the murders as suicide makes the case particularly unusual.

“I believe that this is unique even internationally,” said Johan Frisk, the police inspector in charge of the investigation.