A man bit the ears of another man after catching him trying to perform a sexual act with his sister.
Anthony Dempsey, aged 24, appeared at Letterkenny District Court in Co Donegal where he pleaded guilty to a savage assault on John Kelly.
Gardaí were first alerted to the brutal attack when a woman noticed a man on the upstairs window ledge of a house at St Eunan's Terrace in Letterkenny on November 5 last year.
The man had a bloodied face and was in a distressed state as another man tried to pull him back into the house.
The man managed to run away and was taken into another house by two women.
The women contacted Gardaí and they found John Kelly in a distressed and emotional state. He was rocking back and forth and was bleeding heavily, was in a lot of pain and the tops of his two ears were missing.
Gardaí called to the house where Mr Kelly had first been seen and Dempsey answered the door.
Garda Gerry Fee said it was obvious that Dempsey has washed his face and that there had been blood splattered on the walls, but they had been wiped in an attempt to hide it.
He said everyone in the house was under the influence of an intoxicant and that Dempsey had become agitated and had punched the wall and the worktop.
He was arrested but was initially unfit to be interviewed.
He later admitted punching Kelly in the face and in the body but denied biting off his ears.
He said the reason for the attack was because he caught Kelly masturbating over his sister when she was asleep in a room.
Garda Fee said he did not believe this, saying he did not believe Dempsey's sister was in the room or that Kelly had masturbated over her.
Dempsey and Kelly had first met a year earlier when both were undergoing a drug rehabilitation programme in Tullamore.
Dempsey suggested that when they completed the course, they should travel to Donegal and stay with his sister.
Garda Fee said the victim was due to give evidence of his injuries in court and that he had emailed him and sent him a message on Whatsapp but he received no reply.
A medical report showed Kelly suffered numerous injuries including swelling, a laceration to his nasal bridge, swelling to his upper lip and extensive tissue loss to both ears.
He had been referred to a plastic surgeon in Northern Ireland but no report was available despite efforts of gardaí to get one.
Judge John Aylmer was told that Dempsey had 46 previous convictions for a range of offences including dangerous driving, not having insurance, criminal damage, public order, misuse of drugs, possession of a knife and possession of an explosive substance.
Barrister for Dempsey, Mr Shane Costelloe, SC, said his client has a very strong bond with his sister and was convinced that something of a sexual nature was going on.
He said that both Dempsey's parents had been drug addicts and that he had spent three-quarters of his life in either care or in incarceration.
Judge John Aylmer said he needed some time to think about the sentence and adjourned the case until next Wednesday.