The city of Lexington, Miss., has fewer than 1,500 residents and only 10 police officers. But it prompted a 47-page report by the Justice Department’s civil rights division, which found that residents were routinely jailed on illegal “investigative holds” or for unpaid fines, and that they faced excessive force, sexual harassment, retaliation when they criticized the police and racial discrimination.

So intent were officers on collecting fines, said the report released on Thursday, that body camera videos showed them brainstorming additional charges such as “disturbing a business” for a man who ran into the police station to escape a beating. (He was charged with disturbing the peace.)

The report was released after a 10-month investigation, and comes nine years after the Justice Department placed the Police Department in Ferguson, Mo., under federal oversight, in part because of a similar focus on raising revenue at the expense of respecting constitutional rights.

In Lexington, the Justice Department said, more than half of the residents had a warrant for unpaid fines and fees, making them subject to arrest. “Going into town for any reason can mean going to jail,” the report said.

Over the past two years, the Lexington police have made one arrest for every four residents, many of them for noncriminal conduct like using profanity, the Justice Department said. After one woman came in to give a witness statement in a murder investigation, the police arrested her for unpaid fines.

“After an extensive review, we found that police officers in Lexington routinely make illegal arrests, use brutal and unnecessary force and punish people for their poverty — including by jailing people who cannot afford to pay fines or money bail,” said Assistant Attorney General Kristen Clarke, who leads the civil rights division. “For too long, the Lexington Police Department has been playing by its own rules and operating with impunity. It’s time for this to end.”