Trey Eric Sesler, an online animation enthusiast and critic from Texas, is believed to have had a high-powered weapon on him and body armour when he was arrested on Tuesday night.
The bodies of his parents and brother were discovered around 1pm at their Houston home after police received a call from concerned relatives.
Lawton Ray Sesler Jr, 58, his wife Rhonda Wyse Sesler, 57, and their son, Mark Alan Sesler, 26, were found at the home with multiple fatal gunshot wounds from a high-powered rifle.
Someone reported gunshots coming from the home on Monday evening but when police arrived they discovered nothing.
Waller County Sheriff Glenn Smith said: 'This was a scene that had a lot of violence. The house was ransacked.
'Evidence was obtained and it was pretty obvious the connection of the other brother and son to these people.'
Trey Sesler has no criminal record, according to the Houston Chronicle. Read More
His last Video