Nhu Nguyen and Derek Matulina were once friends who fell out over money Nguyen felt Matulina owed him for a drug transaction, Suffolk County prosecutors said today. When the two crossed paths at the Savin Hill T stop on May 7, they began to fight and Nguyen pulled out a gun and fatally shot Matulina, according to the District Attorney's office.

Nguyen was arraigned Tuesday in Suffolk Superior Court following his indictment for manslaughter and firearms charges. A judge ordered him held in lieu of $100,000 cash bail.

According to the DA's office, Nguyen and Matulina met "purely by chance" outside the Savin Hill station. Nguyen demanded his money, and then, the DA's office said in a statement: "Matulina responded by challenging him to a fistfight. For his part, Nguyen allegedly pulled a handgun from his waistband."

"A witness who was friendly with both men urged the defendant to walk away

"Nguyen and Matulina entered the station separately, Broadbent said. A short time later, Matulina approached Nguyen and struck him in the head with an object later found to be a padlock tied to a handkerchief. A friend of Nguyen interceded and physically placed himself between the two men, ending the altercation.

"Video surveillance shows the defendant stepping back and firing one shot directly at the victim's chest before fleeing the scene."

Nguyen, officials say, fled to Portland, ME, where he was arrested a few days later.