Northwestern lawyers filed Tuesday to name the producer of Ultimate Orange, the dietary supplement Rashidi Wheeler ingested shortly before his fatal conditioning drill, as a third-party defendant in the lawsuit filed by the former NU football player’s parents.

The motion states that after consulting experts across the country, the “overwhelming preponderance of medical opinion” is that Wheeler died as a result of a heart arrhythmia, an irregular heartbeat, and not bronchial asthma, as the lawsuit claims.

It goes on to say that the heart condition was “most likely caused by ingredients in the two dietary supplements (Wheeler) ingested shortly before the conditioning drill, Xenadrine and either Ultimate Punch or Ultimate Orange.”

Laboratory testing by the Cook County medical examiner revealed that the amounts of ephedrine and caffeine in Wheeler’s blood were similar to that in other patients suffering from the heart condition. The increased amounts in Wheeler’s blood allegedly are from the dietary supplements.

Ultimate Orange, Ultimate Punch and Xenadrine, all legal substances, are banned by the NCAA. The Ultimate products are produced by Next Proteins, Inc.

Linda Will, Wheeler’s mother and one of the plaintiffs in the suit, said NU filed the motion to divert attention from itself.

“They can sue 20 people, but they remain responsible to ensure that it is a safe environment,” Will said. “It was their responsibility to call for help. The responsibility still lies solely with Northwestern and their failures.”

Alan Cubbage, NU’s vice president for university relations, said the university would not comment outside the motion.

Will, who recently rehired Johnnie Cochran and his Chicago partner James Montgomery to represent her in the lawsuit, held a press conference Wednesday in Chicago marking the eight-month anniversary of her son’s death.

At the press conference, Cochran criticized the NCAA’s failure to reprimand NU, as well as the school’s failure to discipline its football staff.

“Many parents, as well as present and past students at Northwestern, are outraged that nothing has been done by the university or NCAA to protect current and future student athletes,” Cochran said. “I’m calling for immediate and decisive penalties and corrective action by the NCAA and Northwestern University.”

The lawsuit, filed in the fall, names seven members of NU’s athletic department, including Director of Athletics Rick Taylor and head football coach Randy Walker.

Will announced that she was hiring Cochran the day of Wheeler’s funeral in August, then fired him on Nov. 28 in favor of a high-profile Chicago firm, Powers, Rogers and Smith. She said her decision to rehire Cochran was personal.

“My mission now is to ensure that no one else dies because of (NU’s) negligence,” Will said. “Northwestern needs to fire the entire athletic department so they can regain the fine reputation they once enjoyed.”

The Daily’s John Eligon contributed to this

report.