The NYC police commissioner just resigned amid a federal probe. Here's a look at the 4 investigations embroiling City Hall right now.

The commissioner of the biggest police department in the country resigned Thursday, days after having his phone seized by federal agents as part of one of multiple, ongoing criminal investigations into New York City Mayor Eric Adams’ administration.

Edward Caban, the New York City police commissioner, announced his resignation in an email on Thursday, saying "news around recent developments" had "created a distraction" too big for him to focus on the job of being NYC's top cop.

“The N.Y.P.D. deserves someone who can solely focus on protecting and serving New York City, which is why — for the good of this city and this department — I have made the difficult decision to resign,” Caban wrote.

“I am unwilling to let my attention be on anything other than our important work, or the safety of the men and women of the NYPD,” he added.

What was the mayor’s response?

At a hastily arranged press conference, Adams said he accepted Caban's decision to resign and appointed Tom Donlon, a retired FBI official who previously served as New York's director of Homeland Security, as interim police commissioner.

The 4 federal investigations

The development comes amid at least four ongoing federal investigations into the Adams administration — and have ensnared several of his top officials.

Here is what is known about each:

The police commissioner and his brother

Last week, federal agents seized Caban's phone as part of an investigation being conducted by the U.S. attorney's office for the Southern District. According to the New York Times, that probe has "focused at least in part on a nightclub security business owned by the commissioner's twin brother, James Caban," a former police officer who was fired in 2001. Caban also had his phone seized, according to the paper.

The Adams campaign

According to the Times, federal investigators are examining whether the Adams campaign conspired with the Turkish government to receive illegal foreign donations. "Federal prosecutors were also investigating whether the mayor pressured the Fire Department to sign off on the opening of a high-rise consulate building for the Turkish government and whether he accepted pricey airfare upgrades from Turkish Airlines, which is owned in part by the Turkish government," the Times reported. Last November, federal agents searched the home of Brianna Suggs, Adams' fundraising chief. Adams himself was subpoenaed in July — eight months after federal agents seized his cell phones and an iPad while he was leaving an event in Manhattan.

Adams’ Asian affairs adviser

Earlier this year, agents searched the homes of Winnie Greco, the mayor’s special adviser and director of Asian affairs, as part of a separate federal investigation. "The focus of that investigation is also unclear," the Times noted, "but it is being conducted by a prosecutor’s office that has brought several high-profile cases in recent years against people accused of acting illegally on behalf of the Chinese government."

Potential bribery scheme

And federal investigators are also examining a possible bribery scheme involving two top officials in the Adams administration: David C. Banks, the schools chancellor, and his brother, Philip B. Banks III, the deputy mayor for public safety. Per the Times, federal agents seized their phones last week as well as the phone of their younger brother, Terence Banks, who runs a consulting firm that has received contracts with agencies that his older brothers oversee.

According to the Associated Press, other officials whose devices were recently seized include Sheena Wright, Adams' first deputy mayor and Timothy Pearson, a mayoral adviser and former high-ranking NYPD official.

Adams has denied any wrongdoing. At Thursday’s press conference, the mayor said he was “surprised as you to learn of these inquiries,” and added: “I take them extremely seriously.”