LOS ANGELES, FEB. 3 -- In the aftermath of quarterback Todd Marinovich's arrest for cocaine and marijuana possession, the Los Angeles Times has learned of a pattern in which some University of Southern California football players regularly cheated on their drug tests.

The newspaper discovered in a two-week investigation that some USC football players circumvented drug testing by devising schemes to substitute "clean" urine for their own and also by using masking drugs.

Two days after Marinovich's Jan. 20 arrest in Newport Beach, USC formed a task force to investigate drug testing at the school. The group, chosen by Athletic Director Mike McGee, has yet to offer any recommendations.

Marinovich has since announced he will enter April's NFL draft.

USC, among the first schools to institute drug testing, started testing all its athletes in 1985. Initially, 10 percent of the athletes failed the test. USC says only 2 percent of the recently tested athletes failed.

"We heard in the fall of '89 that one of our athletes may have cheated on a test -- not how it was done," McGee said Friday. "At that point, we put into motion what we thought were some extra precautions that involved, in addition to a technician, a university administrator to be an observant."

Nevertheless, interviews with more than 15 players and former players indicate the following has happened since the program was started in 1985: Urine believed to be "clean" is acquired from athletes and other students on campus. If little scrutiny is expected, the urine is brought to the testing area in a vial, bottle or package and simply poured into the testing cup when the observer isn't looking. If the player expects to be watched, a bladder pack filled with "clean" urine is strapped to a part of the body not visible (under an arm or under a shirt) with a tube running to the pelvic area in order to simulate urination. The attention of testing officers is diverted by athletes, allowing other athletes to pour "clean" urine into the testing cup. A number of masking drugs, available at so-called "head shops" in Southern California, are purchased by athletes and these are taken with moderate success. If given 24 hours notice that they are going to be tested, athletes consume vinegar, cranberry juice or water in large quantities to flush illegal substances out of their system.

"The situation was such that it seemed that they {tried to} catch those who they wanted to catch," said former USC defensive back Brandon Bowlin, referring to the frequency with which some athletes were tested.

A former offensive player explained it this way: Players "would take someone else's {urine} and have it in a bag that was taped to their back. They would then run an IV {intravenous} tube down between their legs. Then, they would have a clamp at the end that released the urine when you took it off . . . like you were really going to the bathroom."

Another recent offensive starter said that USC testing procedures were so lax that it allowed cheating.

"Some of the guys knew how to beat the drug testing," he said. "They would take a small bag and put some clean {urine} in it and hold it under their arm. It didn't matter whose you had as long as it was clean. . . . The person who would be responsible for watching you would walk into the stall, but never knew if you cheated or not. I really don't think USC knew about this."

McGee said Friday that if USC's program has deficiencies, so do others.

"Maybe we don't have the latest understanding of techniques that might be used to cheat on tests," he said. "You're saying our problems are in observation. My point is, we're not the only ones that have been fooled or not fooled."

For instance, the NCAA was testing USC football players for postseason games.

"If I've said anything that makes you think we have all the answers, I'll be the first one to say we don't," McGee said. "But we are committed to a testing program. We think it has value."