DETROIT — Uber has fired more than 20 employees after a law firm investigated complaints of sexual harassment, bullying, discrimination and other violations of company policies.

The recent firings included both managers and lower-level workers, some of whom retaliated against employees after they complained about bad conduct at the ride-hailing firm, said Bobbie Wilson, a Perkins Coie partner involved in the investigation.

Uber Technologies retained the firm after former engineer Susan Fowler posted a blog in February about sex harassment at the company. Fowler wrote that on her first day at work her boss propositioned her in a series of messages.

The Perkins Coie probe is separate from one being done by former Attorney General Eric Holder. He is likely to make broader recommendations on how to change Uber’s culture when his report is released publicly next week.

Separately, Uber announced Tuesday that it has hired Apple marketing executive Bozoma Saint John, who will be Uber’s chief brand officer. She ran global consumer marketing of Apple Music and iTunes. Her task at Uber will be to improve its brand image so people like it as well as they like the company’s ride services, an Uber spokesman said.

After Fowler’s blog posting, Uber set up a 24-hour hot line to take complaints from employees, and hired Perkins Coie to investigate them. The firm checked into 215 complaints, and 57 remain under investigation. The hot line will remain in operation.

The probe into Fowler’s complaints is still under way, and Wilson wouldn’t say if any of those fired, or 31 other employees placed in counseling, were involved in that.