The jury found Jairon A. Gonzales Martinez, 24, guilty of second-degree murder and assault charges in the June 2011 killing of Rumaldo Bethancourt Lopez, 29, also of Brentwood.
Gonzales Martinez was one of several men involved in the attack outside Brentwood's Fiesta Pool Hall that also left Ramiro Garcia, 33, of Central Islip, with serious head injuries, the Suffolk district attorney's office said.
It was the first murder case with a videotaped interrogation to go to trial since Suffolk police began making such recordings in 2010, attorneys said.
The conviction comes almost a year after State Supreme Court Justice Mark Cohen tossed out a written confession and much of an oral confession because the video showed detectives ignored Gonzales Martinez's attempt to exercise his right to remain silent.
Attorney Michael Brown of Central Islip said his client didn't react when the verdict was announced Thursday.
"My client has maintained his innocence since the inception of this matter and is looking forward to being vindicated in the appellate courts," Brown said.
Besides murder, Gonzales Martinez was also found guilty of gang assault and second-degree assault in the death of Bethancourt Lopez, and first-degree assault in the attack on Garcia.
"This defendant used a pipe for his brutal, unprovoked attack on two defenseless victims, killing one and beating the other man so severely he was in a coma when taken to the hospital," District Attorney Thomas Spota said in a news release.
Sentencing is scheduled for May 22.
With Andrew Smith