Police are looking for a third suspect in the murder of a young man who was killed after an apparent "threesome" in Park Slope. While anonymous police sources have said they believe the sex was consensual, the woman involved maintains that she was raped by the murder victim.

On June 19th, around 4 a.m., EMS discovered Mano Ikonomidis bleeding to death from stab wounds in his chest at 355 16th Street. The 20-year-old, who had also been beaten, died at Methodist Hospital. Police believe that Ikonomidis and another man had been engaged in a consensual threesome with an unnamed woman. Police sources told DNAinfo that the woman "became upset after one of the men began to record the encounter and asked to be taken home."

After one of the men drove her home to Staten Island, she allegedly told her boyfriend, Christopher Membreno, that she had been raped. The Daily News reports that Ikonomidis's girlfriend, who was not involved in the alleged threesome, soon received "an ominous Instagram message" informing her that "your boyfriend f----d up and will be taken care of."

Membreno and two others allegedly went to the Park Slope building and attacked Ikonomidis with a knives and baseball bats.

Membreno, 24, was arrested, as was Gabriel Dos Santos. Both are charged with murder and criminal possession of a weapon; Dos Santos is also charged with gang assault.

In a jailhouse interview, a distraught Membreno told the News that he was not aware that investigators believe the sex was consensual. "I just wanted some f---ing justice," he told the tabloid. "I wanted to hold him until the police got there." He added, while reportedly weeping, "I threw my life away for a f---ing lie? My life is over because of a f---ing lie?"

However, his girlfriend's lawyer spoke to the News as well. "She’s claiming that she was raped, that it was not consensual and that she said no over and over again," Joseph Mure told the paper. "She’s not doing very well. She’s having a very difficult time. Obviously she is upset about everything that transpired."

The third suspect in the attack is described as being 5'9" and about 165-170 pounds and was last seen wearing a T-shirt, jeans, and sneakers. Authorities released video:

Anyone with information in regards to this incident is asked to call the NYPD's Crime Stoppers Hotline at 1-800-577-TIPS (8477) or for Spanish, 1-888-57-PISTA (74782). The public can also submit their tips by logging onto the Crime stoppers website at WWW.NYPDCRIMESTOPPERS.COM or by texting their tips to 274637 (CRIMES) then enter TIP577.