Prince George’s County Police Chief Hank Stawinski, who has led the department since 2016, resigned Thursday — the same day fresh allegations of discrimination within the department came from officers suing the county and amid calls for his ouster by the head of the local NAACP.

County Executive Angela D. Alsobrooks (D) said in a statement that she had accepted Stawinski’s resignation effective immediately and said she would hold a news conference at noon Friday.

A spokesman for Alsobrooks declined to comment before her news conference, and Stawinski did not immediately respond to requests for comment.

The announcement of his resignation comes as chiefs across the country confront a rise in animosity toward and distrust of law enforcement amid the killings of black men in police custody.

Prince George’s County Council member Deni Taveras (D-District 2) said Stawinski did a “very good job in terms of lowering crime rates and creating a good system of community engagement” but “there were challenges.”

“The problem is that the county is seeking something different,” Taveras said. “That is the tragedy and necessity of the matter — given the time, given the social climate, the county wants something different.”

Before the announcement of Stawinski’s resignation, officers suing the county alleging that the Prince George’s County Police Department is biased against black and Hispanic employees filed an expert report that they said shows systems of discrimination and retaliation exist within the department. Bob Ross, the head of the Prince George’s chapter of the NAACP, said the group planned to hold a vote of no confidence in Stawinski’s leadership.

“This is the last straw that has broken the camel’s back, the filing of this suit,” Ross said.

He said Thursday night that he was pleased to see Stawinski resign and that members of the local NAACP spent their meeting talking about what they want to see in the next police chief.

“There was a lot of pressure being applied,” Ross said. “This is something that didn’t happen overnight.”

The original lawsuit, filed with the backing of the ACLU of Maryland and the Washington Lawyers’ Committee for Civil Rights and Urban Affairs in December 2018, claims that the department routinely deploys harsher disciplinary measures against officers of color. The lawsuit also asserts that the department systematically demotes those who complain of biased treatment.

In response to Stawinski’s resignation, Dennis Corkery, an attorney with the Washington Lawyers’ Committee for Civil Rights and Urban Affairs, called for the focus to remain on the alleged systemic injustices within the department.

“This is an important step, but there is still much more that needs to be done to reform the racist culture within the police department,” he said. “Stawinski is still a defendant, and we still have claims against the county.”

Del. Erek L. Barron (D-Prince George’s), the chairman of the county’s House delegation, said he was not surprised to hear of Stawinski’s resignation.

“It just seemed like he was hanging by a thread,” Barron said, given the federal discrimination lawsuit by officers and a number of “bad incidents that rival some of those that have gone viral across the country.”

Barron, who has introduced a police transparency bill in Annapolis for several years, added that Stawinski has, “relatively speaking, been an ally” on moving the legislation.

Stawinski, the son of a county police officer, ascended to head the department when he became interim chief after the retirement of Mark A. Magaw in late 2015. Early the following year, Stawin­ski was unanimously confirmed as chief by the County Council. He also served on state and national law enforcement groups, including as president of the Maryland Chiefs of Police Association.

He graduated from DeMatha Catholic High School in Hyattsville and later earned a biology degree from Boston College. His county roots pulled him home to enter the police academy in the early 1990s, when he began more than two decades of rising through the ranks, working investigations as a homicide detective and later serving as commander of a busy patrol district.

Eventually, Stawinski became the deputy chief of daily operations and focused on data-driven analysis to help fight crime, an approach he carried into the chief’s office.

During his path to confirmation, elected officials praised Stawinski’s ability to communicate with leaders and the public.

Throughout his tenure as chief, Stawinski said he tried to be forthright with residents, even during incidents that cast his department in a negative light, such as when police charged an officer with fatally shooting a handcuffed man inside a cruiser in January. The county announced charges against the officer within 24 hours.

Despite generally declining crime rates under much of his tenure, he has faced pushback in recent years from the lawsuit filed by the officers of color, who updated their complaint Thursday with the additional report from an independent expert they hired.

Representatives from the county did not immediately comment on the latest filing, but in the past, they have declined to speak on the matter citing the pending litigation. The county has largely denied the allegations in court filings.

“Defendants deny that they have engaged in racial discrimination or retaliation or disability discrimination employment,” the county said in court documents filed March 10.

The county has also asserted in court filings that the cases from the officers suing the county do not represent a pattern or practice of discrimination but rather are isolated events.

“Stawinski was the chief, so he was 100 percent responsible. He had every opportunity to fix the problem and he chose not to,” said Thomas Boone, a lieutenant with the department and a plaintiff in the case. “This is a new beginning, a new opportunity to start putting things in place that will allow everyone in the community to succeed.”

In the expert report, Michael Graham, a former assistant sheriff in the Los Angeles County Sheriff’s Department, referenced data from the police department’s disciplinary files that he said shows officers of color were far more likely to be investigated, disciplined and terminated. He also detailed more than two dozen incidents of what he identified as racist conduct in the department, and he said only half were investigated.

In the report, Graham described some of the allegedly racist events that transpired without investigation or disciplinary repercussions. He highlighted an implicit bias training in June 2018, when a group of white officers allegedly walked out. Graham said he found no evidence of investigations or disciplinary consequences.

The expert report, which had large redactions, also identified complaints from community members and politicians about racist or abusive conduct.

Joe Perez, a former officer with the department and a plaintiff in the case, has called on the county to release the unredacted report. Perez, who is also the president of the Hispanic National Law Enforcement Association, said the chief’s resignation is a vital step toward progress in the department.

“This is not over; this is just the beginning,” he said. “But with him gone, there is a light at the end of the tunnel.”

Many of those involved with the lawsuit also filed a complaint with the U.S. Justice Department asking for a review of whether officers of color are treated unfairly or are unjustly demoted or disciplined after exposing wrongdoing. Justice Department officials have previously declined to comment on the “existence or nonexistence” of an investigation involving Prince George’s County police.

Ovetta Wiggins, Clarence Williams, Luz Lazo and Dan Morse contributed to this report.