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PHILADELPHIA (CBS) — Three more men have been charged in the murders of four people found dead in a Southwest Philadelphia basement.

Police say 36-year-old Nasir Robertson-Moss, 34-year-old Keith Garner, and 30-year-old Robert Long have all been charged with murder, robbery and other related offenses.

Mugshots from left to right: Robert Long, Nasir Moss-Robertson, and Keith Garner.

Jahlil Porter was already charged in the case.

Two men and two women were found shot and killed execution-style in the basement of the home on the 5100 block of Malcolm Street on Nov. 19.

The victims were identified as 17-year-old Yaleah Hall, 20-year-old Tiyaniah Rakele Hopkins, 28-year-old Akeen Mattox, and 31-year-old William Taylor. Mattox and Taylor were brothers, while Yaleah and Hopkins were sisters. They were all pronounced dead at the scene.

Police said the killings were over a drug deal gone bad. Police say while Mattox and Taylor were renovating the home, they came upon a drug stash. One of the victims tried to broker a sale, but the suspects came to the home with the intention of robbing them, said police.