TRENTON, N.J. (AP) — The U.S. Justice Department opened an investigation Tuesday into possible civil rights violations by the police department in New Jersey’s capital city.

The investigation in Trenton will focus on allegations that officers have used excessive force, stopped motorists and pedestrians without justification, and illegally searched homes and cars.

“The public must have trust and confidence that police officers will treat them fairly and with respect,” Assistant Attorney General Kristen Clarke, of the Civil Rights Division, said in a written statement. “The Justice Department will conduct a full and fair investigation into these allegations, and if we substantiate those violations, the department will take appropriate action to remedy them.”

Democratic Mayor Reed Gusciora, Police Director Steve Wilson and the head of the city’s legal department were notified of the investigation and have pledged cooperation, federal authorities said.

In a separate statement, Gusciora on Tuesday praised “the overwhelming majority of officers at the city, county, and state level who do the right things every day to keep Trentonians safe.” But he added, “If any members of law enforcement violate the public trust or act in contravention of our state and federal laws, they should and must be held accountable.”

The union representing police in Trenton, a city of about 90,000 people, responded to the probe by citing persistent staffing shortages since 2011, when budget cuts forced the city to lay off 105 officers, or nearly a third of the force.

The union said police responded to 41 shooting incidents over the past 30 days “and have consistently demonstrated commitment, always doing more with less.”

“We understand and respect the purpose of the Department of Justice’s investigation. However, we hope that this inquiry will also shed light on the pressing need for additional resources and support for our officers,” said a joint statement by the New Jersey State Policemen’s Benevolent Association and the union’s chapter in Trenton.

If the federal probe determines the police department has broken federal law, the Justice Department can sue to force changes.

In 2022, the department’s internal affairs unit investigated 128 complaints. Only 14 were sustained, including one criminal violation and 12 labeled “other rule violation,” according to a summary on the department’s website. None of the eight allegations of excessive force, 13 of improper arrest and six of improper search was sustained.