An 18-year-old suspect accused of fatally shooting his 13-year-old sister reportedly turned himself in to Southern California authorities Wednesday afternoon.

Eddie Alvirez allegedly shot his sister with a handgun Tuesday in the bedroom they shared with another sister at the family's home in Lancaster, about 72 miles north of Los Angeles, according to The Los Angeles Times. At least one relative claims the death was an accident.

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The girl was pronounced dead at a hospital.

“She was very loving, happy, smart. Just very outgoing, loved life and, well, she was just taken too fast,” Vanessa Zamora, Alvirez's aunt, said of her niece, according to KTLA-TV of Los Angeles.

Zamora told KTLA she believes the shooting was an accident and said the brother fled the scene because he was scared.

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Investigators are trying to determine if the shooting was intentional, The Times reported.