The teen who was stabbed to death on Sunday has been identified as 14-year-old Sergio Andres Ramirez.
According to autopsy results, Ramirez died of a stab wound to the chest that punctured an artery.
Cameron County Sheriff Omar Lucio said that the autopsy also revealed that the teen was stabbed a second time in the lower chest and a third time on the leg.
Behind bars charged with the teen TMs murder is 30-year-old Jose Miguel Mireles of Brownsville.
Authorities said Mireles has an extensive criminal background that includes aggravated sexual assault of a child, possession of marijuana, of family violence and now first degree murder.
Sheriff Lucio said the teen was in Brownsville visiting his grandparents and had been visiting for about a week.
He said the teen and an older cousin somehow ended up at the wrong address, 6811 Greystone Road where Mireles lived, and that TMs where the stabbing occurred.
The weapon used has not been recovered and Mireles claims he acted in self-defense when the teen and his cousin tried running him over.
Ramirez mother told Action 4 News that she is stunned by the senseless killing of her son.
She said she was supposed to pick him up on August10, but his body will be transported to Houston where he will be buried.