PALMER PARK, Md. (WUSA/AP) - A violent weekend in Prince George's County left four people dead.

The first occurred early Saturday morning in a residential neighborhood. Police say 19-year-old Lester Amilcar Flores-Quintanilla of Alexandria, Va., was shot and killed in the 2000 block of Woodberry Street in Lewisdale. Police say he was walking with two other males and was shot during a possible robbery attempt. They say Flores-Quintanilla is affiliated with the MS-13 gang. Police describe the suspects only as two males armed with handguns.

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Early Saturday evening, a 24-year-old woman allegedly shot and killed 25-year-old Ashley McClurkin inside her home in the 3500 block of Terrace Drive in Suitland. Audrea Blackwell was arrested on Sunday.

On Sunday morning shortly after 8, police say 21-year-old David Shaw of Forestville took out a gun at a home in the 2700 block of Judith Avenue in District Heights. He told six people there that there was going to be a robbery.

Shaw then shot one of the victims in the leg, prompting another person to try to wrestle the gun away. The person was able to get the gun and shot and killed Shaw. Detectives and the State's Attorney's Office are reviewing the case to determine if it was a "justified act of self-defense," say Prince George's County Police.

Shaw and another man were taken to the hospital for their gunshot wounds. Shaw was pronounced dead at the hospital. The other man was treated for his injuries and released.

Sunday, 32-year-old Cristalina Warner was arrested for shooting and killing her 83-year-old grandmother Dorothy Ogden at her home in the 4100 block of Danville Road in Accokeek.

They lived in the home together, say police. According to police, the shooting stemmed from a domestic dispute.