The Winthrop resident accused of stabbing a man in the heart, killing him, and leaving the remains beneath his Winthrop Street porch was held without bail at his arraignment this morning, Suffolk County District Attorney Daniel F. Conley said.

Assistant District Attorney Ursula Knight of Conley’s Homicide Unit told East Boston District Court Judge Roberto Ronquillo, Jr., that JOHN LACOY (D.O.B. 2/9/64) had “a volatile relationship” with the victim prior to the homicide, which is believed to have taken place in the bedroom of Lacoy’s apartment at 429 Winthrop St. more than a week ago.

Due to the advanced state of decomposition, the remains could not immediately be identified. During what Knight called a “rapidly developing and superbly investigated case,” however, State Police detectives assigned to Conley’s office and Winthrop Police learned of a 36-year-old white male with no fixed address who had been romantically involved with Lacoy.

Investigators are confident they’ve identified the victim but are withholding his name until the identity can be confirmed through dental comparisons.

The man’s last contact with his family was on July 25, when he made plans to see a family member about a week later. On July 31, Lacoy allegedly called a friend claiming to be at a beach and saying the man had drowned. On Aug. 3, six days before body was discovered, Lacoy allegedly sent a text message indicating that the man’s body had been discovered beneath his porch.

“He won’t be able to leech off me anymore,” it read.

Witnesses told detectives that Lacoy had not been seen at his second-floor apartment since he stripped his bed and left “a couple of weeks ago.” Lacoy was taken into custody late yesterday after an interview with State and Winthrop police. Lacoy gave a rapidly-changing statement during that interview, allegedly saying at first that he didn’t know the victim, later acknowledging their relationship, and going on to say that they had been in a fight during which the man bit him and after which he disappeared.

Lacoy is represented by attorney John Tardif. He will return to court on Sept. 9.