Fox 2 News found he was active on Twitter, even tweeting around the time Kostial would've been killed. On July 20, Theesfeld tweeted, "you dropped a bomb on me, my number 1 pick for groovy song of the summer."
His Facebook profile says he attended a private school in Fort Worth Texas and then went to a boarding school three hours outside of Fort Worth. He enrolling at Ole Miss in 2016, the same year Ally Kostial left St. Louis for the university.
Theesfeld's father is a doctor who owns a pain management clinic in Ft. Worth. He posted a picture on Facebook of his son in 2013. It says, "Target Practice - 'my son Brandon Theesfeld gun tactical expert.'"
He told several media outlets Tuesday that his son is innocent and that he had his reasons which he cannot yet share.
Sheriff's investigators in Lafayette county have released very little about the investigation.