A South Boston man today admitted to throwing a glass at a fellow bar patron, only to have it shatter and kill 23-year-old Michael DiMaria when it slashed his throat, Suffolk County District Attorney Daniel F. Conley said.

HECTOR GUARDIOLA (D.O.B. 5/8/85) pleaded guilty to the indicted charge of involuntary manslaughter for DiMaria’s death at the Lansdowne Pub just after midnight on Aug. 14, 2010. He also pleaded guilty to two counts of assault and battery with a dangerous weapon for injuries to two others struck by the glass or its shards.

“There is no question that this defendant’s violent, reckless behavior caused Mr. DiMaria’s death,” Conley said. “All that he was to his family and loved ones, all that he could have given them and the world around him, ended because of that decision.”

Assistant District Attorney Ian Polumbaum of Conley’s Homicide Unit recommended that Guardiola serve five to 10 years in state prison; Judge Frank Gaziano imposed a term of four to seven years with five years of probation upon his release.

In reciting the sequence of events that led to DiMaria’s death, Polumbaum told the court that Guardiola and a female friend were at the bar on the night of Aug. 13 into Aug. 14, as were DiMaria and a group of his friends. As the defendant was leaving, Polumbaum said, he became involved in a confrontation with one of DiMaria’s group after the two bumped into one another. The men exchanged angry words and their respective companions separated them. Neither DiMaria nor the surviving victims were involved in – or even aware of – this incident.

At that point, Polumbaum said, Guardiola picked up a heavy bar glass and threw it at his rival’s head, “stepping into it” to increase the projectile’s velocity. The glass missed its intended target and hit another man in the back of the head, knocking him to the ground. The glass broke and two shards hit a woman in the forehead and neck.

“The bulk of the glass, according to the evidence, continued through the air but with a jagged protrusion,” Polumbaum said. “The jagged portion of the glass penetrated Mr. DiMaria’s neck and shredded his jugular vein.”

Bar staff and patrons detained Guardiola until Boston Police arrived and took him into custody.

Michael Schultz was the DA’s assigned victim-witness advocate. Guardiola was represented by attorney Albert Hutton, Jr.