The 14-year-old who is being accused of shooting his younger sister Monday in their family apartment in northwest Houston turned himself into police.

The Houston Police Department said the teenager turned himself in to authorities Monday night and will be charged with reckless aggravated assault.

The mother of the children told police she was asleep when she was startled awake by the sound of a gunshot. She found her 5-year-old daughter shot and her teenage son in a panic.

She then told police her son grabbed the gun and ran away from their home.

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The little girl was taken to the hospital in critical condition.

It’s unclear what led up to the shooting and if the shooting was intentional or not.

Investigators are also trying to determine how the kids got their hands on the gun.