(CBS) Former Penn State football player and assistant coach Mike McQueary, a whistleblower in the Jerry Sandusky scandal, reportedly amassed large gambling debts and told his players that he was abused as a child, according to an ESPN.com article released Tuesday.

McQueary has filed a $4 million whistleblower lawsuit against Penn State for lost wages after he wasn’t retained. Separate of that, he’s expected to be a key witness, ABC.com reported, for the prosecution in an upcoming criminal trial of three former high-ranking Penn State officials who are facing conspiracy charges: former president Graham Spanier, former athletic director Tim Curley and former vice president Gary Schultz.

New information on his background came to light when ESPN.com released its in-depth story Tuesday.

From ESPN.com:

According to several of his classmates and teammates, McQueary developed a compulsive gambling habit at Penn State. He bet and lost thousands of dollars on poker and sports wagering, mostly on pro football, though he also bet, several of his former teammates say, on Nittany Lions games. One former teammate specifically recalls that Big Red bet and lost on his own team in a November 1996 game against Michigan State at Beaver Stadium. With McQueary serving as a backup on the sideline, favorite PSU won on a late field goal 32-29 but didn’t cover the eight-point spread.

As his losses mounted, McQueary owed thousands of dollars to a bookie, a debt that was eventually erased by his father, several people say. A college friend recalls urging McQueary to slow down. “It got pretty bad,” the friend says, “and it just kept snowballing and snowballing. He was very impulsive.”

Also from ESPN.com, in regards to McQueary not intervening immediately when he saw Sandusky initially abusing a young boy:

McQueary confided in his players something he hoped would make them understand how he’d reacted at the time. He told them he could relate to the fear and helplessness felt by the boy in the shower because he too was sexually abused as a boy.