Authorities in Santa Monica, California have searched the home of 86-year-old Russell Weller.
Police say the elderly driver plowed through an open-air market Wednesday, leaving nine people dead and more than 40 hurt.
Police say they were looking for medications and evidence of his ability to drive in the search. Santa Monica Police Chief James Butts says evidence shows Weller recently struck the back of his garage at least twice with his car.
He didn't say exactly how police came to that conclusion.
Initial results from a blood test showed no traces of alcohol or drugs like antidepressants or hallucinogens.
Butts says it simply appears to be a case of a driver that, "may not have been as competent as he needed to be to drive."