A 12-year-old girl is accused of smothering her 8-year-old cousin while the younger child was asleep.

According to reports, the incidents occurred in Humboldt, Tennessee. The accused 12-year-old, in a fit of anger, allegedly smothered her cousin Demeria Hollingsworth after the two argued over an iPhone. They had just returned from a trip with their grandmother when the tragic event took place.

Captured footage from July 15 shows the dreadful scene inside a bedroom. The footage reveals the older girl using bedding to smother the younger one, who was sleeping on the top bunk. The video also shows the older cousin wiping the child’s body and repositioning her after she had passed away.

The 12-year-old now faces charges of first-degree murder and tampering with evidence. Prosecutors are considering trying her as an adult, with her 13th birthday only weeks away.