BLEEDING on his living room floor, a college student mortally stabbed by a friend during a fight over a stolen Sony PlayStation whispered the name of his accused killer before dying, a police source said yesterday. "Manny did it," 19-year-old David Higgins told a neighbor - referring to Emanuel Polanco, the 21-year-old drifter whom Higgins and his parents had welcomed into their Queens home, the source said. Cops investigating Higgins' murder were hunting for Polanco last night, sources said. Detectives said Polanco also used a bat to club Higgins' mom in the head about 5:30 p.m. Monday after allegedly stabbing the Bronx High School of Science graduate. "What could a person gain from hurting people who were so sweet?" asked Lorraine Townsend, 40, the victim's cousin. "They were trying to help him." His hands still bloody, Polanco strolled into a nearby Fresh Meadows deli minutes after the slaying - and quenched his thirst with a $1.50 iced tea, police and witnesses said. The houseguest from hell gave no hint of the carnage he allegedly had left in his wake. "He didn't seem nervous," said Pascal Joseph, 50, one of two clerks who saw Polanco at the Express Deli on Parsons Blvd. "He didn't seem agitated. He was deadly calm." Polanco - who had lived in several group homes before Higgins' family generously welcomed him into their house - told the deli workers that he had injured his hand during a fight and asked for napkins to soak up the blood. Before leaving with his pomegranate-flavored drink, Polanco tossed the napkins and what appeared to be gauze in the trash, workers said. Police took surveillance footage from the store, but officials wouldn't comment about what, if anything, had been recorded. Higgins met Polanco about a year ago while they were both working at Woodhaven Lanes, a Queens bowling alley, the murdered man's relatives said. Concerned that Polanco had nowhere to stay, Higgins, a Hunter College student, asked his parents to let his new pal sleep at their 162nd St. home. The parents agreed, but asked Polanco to leave a couple of weeks ago, believing he was stealing from them. "He was furious," a neighbor said. On Monday, Polanco broke into the family's house and was ransacking the place when Higgins, a former high school wrestler, came home and confronted him about the missing PlayStation, police sources said. Polanco allegedly stabbed Higgins repeatedly before the young man's mom, Verne Culberson, 56, came home. Polanco clubbed her in the head with a bat after demanding cash, the sources said. When Culberson ran to a window and screamed for help, Polanco fled, the sources added. Higgins was taken to New York Hospital Medical Center of Queens, where he died about 8:45 a.m. yesterday. His mom was in stable condition last night at the same hospital, police said. "He's gone," the devastated mom told relatives from her hospital bed. "He's gone." Higgins had aspired to become a writer, and his professors said he had a world of potential. "It's such a shame," said Marie Warmbold, an adjunct professor at Hunter. "He was a smart kid. "I bet he could have accomplished a lot."