A sex offender accused of the teen-in-the-lake murder might have stopped taking his medication, a former friend has claimed.

Tragic Ayleen Ambs, 14, was found dead in the Teufelssee lake in the central German state of Hesse, Germany, after the suspect, who has been named as Jan-Heiko Pflur, 29, groomed her online, according to the police.

Pflur had earlier spent 10 years in a psychiatric hospital after trying to rape an 11-year-old girl, according to German daily Bild.

Now a childhood friend has revealed how Pflur allegedly failed to take prescribed drugs that blunted his sexual drive.

The friend is named in the newspaper as Patrick E., 31, and he said that he stopped communications with Pflur two years ago.

He is quoted as saying: “Jan actually has to swallow pills so that he doesn’t get horny.”

Patrick E. told Bild that agreeing to be medicated was one of the requirements for Pflur to be released from the psychiatric ward.

But he said: “But he doesn’t take them because, according to him, it would cost money. He was also not allowed to drink alcohol. I think because of the sinking inhibition threshold.

“When I asked him about the girls he was harassing, he always said, ‘I didn’t do anything.”

Patrick E. added: “Jan will be a danger for life. He should be locked away forever. Jan should never have come out of the psychiatric ward, I said that back then.”

He also told the newspaper: “Even my father used to say ‘Someone like that doesn’t belong in humanity’.

“After Jan was released from the psychiatric ward, even his family did not leave him alone with his siblings’ children. When Jan looked after her, someone always had to be there.”

And another friend of the suspect, who has not been named, told how Pflur was always looking for sex.

They reportedly said: “Jan went to many festivals – Kerb in Waldgirmes, rose festival in Steinfurth, ox festival in Wetzlar, Gallus market in Wetzlar, funfair in Leun.

“He was more or less always on the hunt.”

Police in Hesse , central Germany, have said that Ayleen was led to the lake by the prime suspect who is said to have met the teen after grooming her online.

Ayleen went missing from her home in the village of Gottenheim, in the neighbouring state of Baden-Wuerttemberg, in south-western Germany, near the French border.

Her body was found in Teufelssee lake on Friday, 29th July, some 300 kilometres (186 miles) away.

Jan-Heiko Pflur was seized and questioned in Kassel a day before Ayleen’s body was found.

Her clothes were reportedly found in the suspect’s apartment.