Lawyers vying for leadership of the sexual assault cases against Uber Technologies Inc. have turned on each other, with accusations of “professional misconduct” and a “smear campaign.”

Behind the fight are two proposed leadership teams, one of which involves lawyers at the four plaintiffs’ firms litigating Uber sexual assault cases for three years in California’s state courts. But the objections became more heated after one of them, William Levin, singled out Rachel Abrams, a former partner at his San Francisco-based firm, Levin Simes, as unfit to lead about 150 federal cases in multidistrict litigation in California’s Northern District.