Source: An off-duty police officer riding a bicycle was struck and killed late Sunday by a car in Philadelphia's East Mount Airy section, authorities said this morning. Homicide detectives are investigating the possibility the officer was deliberately mowed down and are questioning a man with whom he had argued earlier. Officer Marc Brady, 32, an eight-year veteran of the force assigned to the 22nd District in North Philadelphia, was hit about 11:40 p.m. while riding his bike at Musgrave Street and East Meehan Avenue, police said. He was rushed to Albert Einstein Medical Center, where he was pronounced dead at 12:05 a.m. today. Police initially described the death as a hit-and-run, but Police Commissioner Charles H. Ramsey later told reporters at Police Headquarters that the motorist stopped his white Acura nearby and remained with the vehicle. Homicide detectives confirmed that they are investigating the possibility the killing was intentional and were questioning a man with whom Brady had argued earlier Sunday. The nature of the argument was not disclosed. Law enforcement sources said the officer had been wounded in 2010 an off-duty shooting stemming from an unspecified domestic dispute. Updated Source: Kareem Alleyne, 35, was charged Monday with homicide by vehicle and manslaughter after police said he intentionally struck Officer Marc Brady's bicycle with his car. Alleyne, of Mount Airy, had just left his girlfriend's house around 11:40 p.m. Sunday when he saw Brady riding on Musgrave Street near Meehan Avenue in the direction of the woman's home, said Philadelphia Capt. James Clark. Brady and the woman, who was not identified, have several children together, and police said Brady sometimes visited the children at her home. But he and Alleyne "had bad blood between them," Clark said. When Alleyne saw Brady biking toward him, Clark said, he swerved his white Acura in Brady's direction and struck him head-on. Brady, 32, who lived a few blocks from the scene, was pronounced dead at Albert Einstein Medical Center shortly after midnight. Sources familiar with the investigation said Alleyne told police he struck Brady by accident. He drove a short distance after the crash, Clark said, then stopped his car and waited for police to arrive.