(CBSDFW.COM/CNN) — A man in Texas allegedly shot and killed his grandmother while she was sleeping and then tried to stage her death as a drive-by shooting, authorities said Sunday.

The Harris County Sheriff’s Office said Marcus Hanson, 23, has been charged with the murder of his grandmother, 68-year-old Shelia Crosslin.

Deputies responding to reports of a drive-by shooting in north Harris County just before 1 a.m. found the woman “lying in her bed and deceased from apparent gunshot wounds,” the sheriff’s office said.

Hanson told deputies he heard “someone begin shooting into their home,” the release said. He said he grabbed a handgun, went outside and fired several times at a vehicle fleeing the scene, according to the release.

Marcus Hanson (Source: Harris County Sheriff’s Office)

Hanson “attempted to stage the scene,” Sheriff Ed Gonzalez said in a tweet.

While at the house, the deputies received a call about a second shooting victim in a home next door. There they found an 11-year-old girl who had a graze wound to the head.

“Possibly in retaliation,” for the alleged drive-by shooting, “a relative of the female returned gunfire & inadvertently struck an 11-yr-old female in an adjacent residence causing her minor injury,” Gonzalez tweeted while the investigation was underway.

The girl was treated on scene for minor injuries and released to her parents.

“After conducting several interviews and reviewing all physical evidence,” investigators charged Hanson with his grandmother’s death, according to the release.

“No motive for the shooting has been determined,” the sheriff’s office said.

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