A man decapitated his girlfriend and then had sex with her head.

A Russian man has been declared insane after decapitating his girlfriend and performing sexual acts on her head while wearing one of her dresses.

Aleksandr U., 23, killed Viktoria V., 22, in July last year after she discovered him wearing her clothes and make up. Viktoria attempted to end the relationship, police report, but was instead brutally murdered.

Police discovered Viktoria’s decapitated body and her head, which Aleksandr had used to give himself oral sex after her death, in the Russian city of Voronezh. Her body had been stabbed 53 times.

According to news site newsru.com, Aleksandr had been drinking and taking drugs, including “bath salts”, a synthetic drug composed of mephedrone, on the night of his murder.

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The punk musician, known as “Pussy” to his friends, had a habit of wearing women’s clothing.

He had previously been thrown out of his band, Easy Riders, when his bandmates discovered his fondness for masturbating while dressed in Viktoria’s clothes.

Although his friends questioned him about the practise, “Pussy” never gave them a straight answer.

At trial this week, Aleksandr was detained indefinitely in a psychiatric institution after being declared mentally ill.

The surnames of the victim and the accused have not been released to the public in accordance with Russian law.