Police now believe a Garland teenager died after being shot by his friend, rather than committing suicide.
Matthew Cisneros was found dead inside his home on Plymouth Drive on Feb. 26. Officers found a gun lying beside him.
But after performing and autopsy and interviewing the 13-year-old's friends and family, investigators determined he did not pull the trigger.
A 12-year-old boy was taken arrested at school on Friday on manslaughter charges.
The juvenile suspect admitted to police that he had been playing with the gun at his friend's house. He said he thought it was unloaded when he pulled the trigger.
"We truly believe, that this 12-year-old believed this gun wasn't loaded at the time he pulled the trigger," said Joe Harn of Garland police.
Police did not release the 12-year-old's name.