A prison guard helped smuggle in a gun used to kill one of Turkey's most notorious murderers, Justice Minister Bekir Bozdağ said yesterday.

Ahmet Suphi Altındöken, 27, died shortly after being shot on Monday in Kürkçüler Cezaevi prison in southern Turkey by a fellow inmate.

He was convicted last year of the gruesome murder and attempted rape of 20-year-old student Özgecan Aslan, whose mutilated body was discovered two days after she went missing in Mersin province. The crime sparked nationwide anger and protests.

Speaking to reporters in Ankara, Bozdağ said Altındöken's attackers had "help inside and outside" the prison in Adana province.

"Evidence has been found that the gun was smuggled in by an officer there, and now he has been detained," the minister told reporters in the capital Ankara.

Bozdağ added that others suspected of involvement were arrested. "An investigation is underway," he said. He said two senior prison wardens and three prison officers were suspended from duty.

Monday's attack also saw Altındöken's father Necmettin, who was jailed as an accomplice to the murder, receive a gunshot wound. His life is not thought to be in danger.

Bozdağ said the killing was unacceptable. "This is really a security weakness," he said. "Therefore whoever has neglect, fault and intention in this issue will face every kind of legal and administrative investigation."

Aslan's murder in February last year served as a focal point for protests against violence directed at women.