Man beaten to death after threesome gone wrong .

Brooklyn man, 20, is beaten with a baseball bat and stabbed to death after a 'threesome-gone-wrong'

What started out Sunday night as a suspected sexual encounter involving two men and a woman ended with one of the male lovers getting pounded with a baseball bat and stabbed to death.

The 20-year-old victim was discovered unresponsive in the Park Slope section of Brooklyn after sustaining at least five stab wounds to his chest and back.

The New York Daily News reported, citing unnamed police sources, that the deadly violence had been preceded by an amorous encounter involving the 20-year-old victim, another man and a woman, both aged 21.

The group sex session reportedly ended on a sour note after one of the men, presumably the victim, started filming the ménage a trois, which made the female participant upset.

The 21-year-old man, who lived at the apartment on 16th Street, then drove the woman home to Staten Island. When he returned, the 20-year-old victim, who did not reside there, took off.

Around that time, the victim’s girlfriend, who was not involved in the orgy, got a message on Instagram that reportedly read: 'your boyfriend f***ed up and will be taken care of,' according to the Daily News.

Sources told the paper surveillance video from the area captured two white men and a black men running after the victim trying to escape from the building.

The victim's girlfriend, who was not involved in the threesome, also received a message on her phone that read:

“your boyfriend f—ed up and will be taken care of,” sources said.

After the man who went to drop the aggrieved woman at her home returned, the victim decided to leave for reasons that were unclear. As the victim tried to leave the apartment building, surveillance cameras captured two white men and a black man chasing him. He was attacked and bleeding from fatal stab wounds, he knocked on the door of a nearby apartment and collapsed, leaving bloody handprints.

“He fell into her house, she opened the door … he was apologizing, ‘I’m so sorry. I’m so sorry,’” said a woman in the building whose relative opened the door. “He says, ‘They hit me in the head, they hit my head with a bat.’ She said there was so much blood just gushing out of him.”

The victim, Ikonomidis, allegedly pleaded with the woman not to call 911 despite having three stab wounds in the chest and back.

“He went to stand up, I don’t know if he was gonna try and leave or what, (and) collapsed on the floor,” the woman said. “She said his whole body started jerking and then they came, he barely had a pulse.”

Ikonomidis died at Methodist Hospital in Brooklyn at 4:33 a.m. His girlfriend arrived at the crime scene hours after the killing and was inconsolable.

She cried: "Oh my God, no! My baby, it can’t be f—ing real! “(Why) didn’t you go home? Why didn’t you listen to me? … He better go to f—ing jail! (Will) you guys get him please? … My baby, my baby, I love you so much.”

Police questioned the 21-year-old man, who was not considered a suspect in the murder. No suspects were in custody as at the time of this report. Police sources also said cops found no evidence the encounter was non-consensual.

“It’s something out of a horror movie,” stunned building resident Carol Petersen, 37, said. Her 18-year-old daughter had heard the victim screaming. “It’s horrible. It’s a nightmare,” she said.

-Dailymail