Because he was going so fast that he was going to kill everybody by running them off the road. Only a crazy person would do something like that, and crazy people are usually prescribed medicine. This made them think to look in his car when they were writing him the ticket and they saw a pill on the floor. Only a drug addict has pills on the floor, so they knew he was using drugs. Since he was so muscular, they knew these drugs were steroids. They said "You like to eat steroids buddy? Do you like to eat 'em up?" and he said "You bet sir, I eat them all day long." Then they left and told him they would see him around and to have a nice day.
and thats the true, factual story of how Joseph Mobareki came to have his house searched.