Friends of Joseph Randle believe brain trauma led to former Cowboys RB's downfall

Some of Joseph Randle's friends think that brain trauma sustained through football may have contributed to the downfall of the now-jailed, former Dallas Cowboys running back.

In a story chronicling Randle's rise to notoriety and fall into incarceration, SI's Dan Greene spoke with the people closest to Randle about the reason for his change in behavior.

During what would be the last game of Randle's career, a Week 7 contest against the New York Giants last season, he hit his head on the ground after being tackled from behind. He did not return to the game with what the team called a "rib/muscle strain," but his friends and family thought it was out of character that he did not return to the field.

Since that game, Randle has been charged with more than a dozen different crimes and is set to go on trial on Monday after spending the last 10 months in jail. Randle's lawyer, Steven Mank, doesn't think his client has connected his behavior with his experiences in football, but other people in his life have. 

Read the full story—the latest in SI's True Crime series—on SI.com.