Florida Atlantic coach Carl Pelini and defensive coordinator Pete Rekstis resigned Wednesday.
A source said the coaches attended a recent social event at which marijuana was used. Although this appears to be an isolated incident, all involved determined it was in the best interest of the program that the coaches resign, the source said.
Athletic director Pat Chun said Pelini and Rekstis tendered their resignations after he confronted both coaches with reports relating to their use of illegal drugs.
"On Monday, I was made aware of these concerns and I immediately reported the allegations to our General Counsel," Chun said at a news conference. "The University acted quickly and decisively to follow up and take action that is in the best interests of our student-athletes and the University overall. I can assure you that we have no information that suggests anyone other than these two individuals engaged in these activities.
"I am personally very saddened for our student-athletes, coaches and staff. I just met with the players a few moments ago and notified them of the news. As you could imagine, the reaction was shock, dismay and disbelief."
Chun released a statement on Pelini's behalf.
"I apologize for exercising poor judgment," Pelini's statement read. "My greatest concerns at this time are for my family, the dedicated FAU players and my staff. I am confident that Pat Chun and the University administration will continue to move the program forward."'
The school announced offensive coordinator and quarterbacks coach Brian Wright has been named interim head coach, effective immediately, for the remainder of the season.
"I have great confidence in his abilities to lead this football program," Chun said. "When I asked Brian to take this role he accepted it without hesitation. He is surrounded by eight assistant coaches that are 100 percent committed to our program and student-athletes."
Pelini, who replaced Howard Schnellenberger as coach after the 2011 season, will leave with a 5-15 record.
Pelini came to FAU after being the defensive coordinator for his brother, Bo Pelini, at Nebraska. Under Carl Pelini, the Cornhuskers' defense improved from 112th nationally in yards allowed in 2008 to seventh and 11th in total defense over the next two seasons.