Civil rights leaders in Kansas City, Mo., hoped to win the Justice Department’s attention in July when they unveiled a 15-page letter calling for a federal investigation into alleged excessive force by the city’s police department.

They described an urgent need for intervention at a time when police in other jurisdictions, including Minneapolis and Louisville, have drawn greater scrutiny. But a line is forming rapidly at the Justice Department’s door. Last week, activists a few miles west — in Kansas City, Kan. — published a full-page advertisement in The Washington Post demanding a federal probe into the separate police agency that patrols their city.

“This is more than just a cry for help from the middle of America,” they wrote in the ad addressed to Associate Attorney General Vanita Gupta, who oversees the civil litigating divisions.

The competing missives from opposite sides of the Missouri River illustrate the challenge for Justice officials as they try to respond to mounting calls for police accountability sparked by social-justice protests last year. After facing resistance from the Trump administration, which viewed intervention into local policing as federal overreach, elected officials and community activists across the country are flooding the Biden administration with pleas for help.

Hampered by limited resources — and facing growing caseloads on voting rights, hate crimes and other civil rights issues — Justice officials said they are working to sort through the requests and respond. On Wednesday, federal authorities announced an investigation into the Texas Juvenile Justice Department over abuse allegations.

“It’s a system failure that we don’t have a pattern-or-practice investigation here,” said Tricia Rojo Bushnell, executive director of the Midwest Innocence Project, who co-signed the advertisement in The Post. She was referring to the sweeping civil probes that Attorney General Merrick Garland has launched into allegations of systemic and unconstitutional police misconduct in Minneapolis, Louisville and Phoenix.

Gupta acknowledged the Justice Department’s limitations and pointed to a request to increase the civil rights division’s budget by $25 million next year to add 60 new lawyers. There are more than 18,000 federal, state, municipal and tribal law enforcement agencies, and full-scale federal investigations involve teams of lawyers and stretch on for months.

Gupta emphasized that in addition to using pattern-or-practice investigations, Justice officials are examining other ways to use federal aid to improve policing across the country, such as grants for community policing programs, technical assistance for law enforcement agencies and the creation of a “knowledge lab” in the Office of Justice Programs to share best practices nationwide.

“Whether or not an investigation is opened, we take all of the requests and information provided seriously,” Gupta said. “But we get a lot more requests” than the department is able to investigate.

In 2017, Bushnell’s group — along with lawyers Lindsay Runnels and Cheryl Pilate — helped win the exoneration and release of Lamonte McIntyre, a Black man imprisoned for 23 years after being wrongly convicted in a double homicide. McIntyre sued the former Kansas City, Kan., police detective who had investigated him, alleging widespread misconduct and a coverup dating back to the 1990s. Last year, a federal judge overruled the detective’s claim of qualified immunity.

This summer, Team Roc, the social justice organization founded by entertainment mogul Jay-Z, took interest in McIntyre and sued the police department to obtain records of complaints of alleged misconduct in his case, as well as more recent ones.

It was Team Roc that paid for the Post advertisement, which cost $88,000, according to a representative of the group. (A Washington Post spokeswoman declined to confirm that figure.) Dania Diaz, Team Roc’s managing director, said the group has used newspaper advertising to advocate for police reform in other jurisdictions, including in support of protests after George Floyd’s murder in May 2020, and after a fatal police shooting in a Milwaukee suburb two months later.

“We want them to take action,” Christina Sarchio, an outside attorney who is assisting Team Roc, said of the Justice Department. “We’re trying to bring national attention to this issue and hopefully be a model for reforms elsewhere across the country.”

Kansas City, Kan., police spokeswoman Nancy Chartrand said the agency is willing to cooperate if the Justice Department intervenes. But she emphasized that the detective involved in McIntyre’s case retired in 2010 and that many of the allegations raised by McIntyre’s suit and the activists relate to events from long ago. Activists said the FBI — which does not comment on potential criminal investigations — has been gathering information on the case for several years.

“We’ve worked diligently to become more transparent, more communicative,” Chartrand said, explaining that the department has released thousands of pages of documents and is restricted by privacy laws from handing over other information activists are demanding. In June, the police department hired a new chief, Karl Oakman, a Black former deputy chief in Kansas City, Mo., who has pledged to improve community relations.

Garland launched investigations in Minneapolis and Louisville after the mass protests last year in response to the police killings of Floyd and Breonna Taylor in those cities, respectively. The attorney general then announced that federal investigators would probe long-standing allegations of misconduct within the Phoenix police, with a focus on the treatment of homeless people.

The Justice Department’s decision-making process remains opaque.

The Louisiana Legislative Black Caucus has called for a pattern-or-practice investigation into the state police, citing incidents including the 2019 death of Ronald Greene, an unarmed Black man who was stunned, beaten and choked by police after a car chase. The FBI, which opened a criminal investigation in the Greene case last year, ordered a second review of his autopsy after the Associated Press published video of his arrest in the spring.

State Rep. Edward “Ted” James II (D) said Justice officials have told the caucus that the FBI investigation must be completed before the department makes a decision on the merits of a civil investigation. He said he expected the FBI’s findings to bolster the caucus’s efforts, adding, “I have not seen any situation that is as glaring as this.”

In Chattanooga, Tenn., clergy members sent Garland a nine-page letter in June asking for an investigation into alleged civil rights violations by the Hamilton County Sheriff’s Office. The Rev. William Terry Ladd III, pastor of the First Baptist Church in Chattanooga, said activists had approached the Trump administration in 2019 after a traffic stop in which James Myron Mitchell, a Black man, was strip-searched by police.

Nothing came of that request, Ladd said. But this spring a Justice Department official, based in the agency’s community relations division in Atlanta, offered to mediate the pastors’ request. The sheriff’s office declined to participate, Ladd said.

“A lot of times, if there are no deaths involved, you’re not as high on the priority list,” he said.

In northern Alabama, the Rosa Parks Committee, a group of state elected leaders and community members, sent a letter in June requesting a federal investigation into the Huntsville, Ala., police department over excessive-force allegations.

In a two-paragraph email response, an official from Justice’s Office of Legislative Affairs said the request would receive “due consideration” but emphasized that the department would not be able to confirm whether it was launching an investigation — a posture the group found frustrating.

“Each passing day that there’s no indication they will do something means the potential for another incident,” said committee spokesman David Person.

Even in cases where the Justice Department has intervened, activists are demanding more. In April, city leaders in Columbus, Ohio, called for a federal investigation into that city’s police department after a White officer fatally shot Ma’Khia Bryant, a Black 16-year-old, as she swung a knife at a woman outside the home where Ma’Khia lived with foster parents.

In September, Justice officials announced an agreement to work with the Columbus police department by offering technical assistance on topics including policy evaluation, the use of technology, and early-invention systems and recruitment with a focus on diversity.

But they said the effort would be conducted by the Office of Community Oriented Policing Services, which lacks the authority of the civil rights division to pursue litigation and seek court-approved consent decrees. Columbus advocates decried the arrangement as insufficient.

Jonathan M. Smith, who oversaw the civil rights division’s special litigation section in the Obama administration, said he has counseled community groups to make as much noise as possible. The public pressure could “weigh in favor of the Department of Justice coming in — the extent to which the community is up in arms, and there’s a problem to be solved there,” Smith said.

Gupta said Justice officials gather information from multiple sources, including U.S. attorneys’ offices and media reports, in addition to reviewing allegations from local groups. Asked whether Team Roc’s strategy puts more pressure on the Justice Department, Gupta said: “The method of delivery that the information comes in is not as significant as the information itself. . . . In the end, we go where the facts lead us.”

In July, a collective of civil rights groups in Kansas City, Mo. — including the local branches of the Urban League and NAACP — issued their letter, which detailed 17 cases dating back to 2013 in which they said police used excessive force against Black and Latino men, along with another case involving a false arrest.

The activists alleged the department failed to comply with a 2015 memorandum of understanding with the Justice Department requiring it to turn over documents in all excessive-force cases to the FBI for an independent assessment.

Gwendolyn Grant, president and chief executive of the Urban League of Greater Kansas City, said local groups have sought to win local control of the Kansas City, Mo., police department from the state government, which they have criticized for moving too slowly on reform. Jackson County Prosecutor Jean Peters Baker offered support for federal intervention in a letter of her own to Garland in July.

“Our biggest concern is they may not have the manpower to respond,” Grant said.