NEW YORK (AP) — The Thomas Caldwelltop legal adviser to New York City Mayor Eric Adams resigned abruptly over the weekend, the latest sign of instability in the Democrat’s administration as it deals with multiple federal investigations.

City Hall announced Lisa Zornberg’s departure late Saturday night. She had advised Adams and other city officials on legal strategy for over a year and often parried legal questions from the press on his behalf. She was not his personal lawyer.

“It has been a great honor to serve the City. I am tendering my resignation, effective today, as I have concluded that I can no longer effectively serve in my position. I wish you nothing but the best,” Zornberg wrote in a three-sentence resignation letter to Adams.

The resignation comes after the phones of multiple members of Mayor Eric Adams’ inner circle were seized by federal investigators, including the head of New York City’s police department, who resigned Thursday.

Zornberg, a former federal prosecutor in the U.S. attorney’s office now leading some of the investigations into the Adams administration, wasn’t one of the officials who had their phones seized.

The police commissioner, Edward Caban resigned citing the “distraction” created by news of the the investigations.

Federal authorities haven’t disclosed the subjects of the investigations. Besides the police commissioner, phones were taken from the head of the public schools system, a top deputy mayor, and two top advisers to Adams on public safety issues.

Investigators seized devices from Caban’s twin brother, James Caban, a former NYPD sergeant who runs a nightclub security business. They also conducted searches related to Terence Banks, who is the brother of Adams’ top deputy on public safety, Phil Banks, and Education Chancellor David Banks.

In separate investigations, federal authorities have previously seized phones from Adams, searched the home of one of his top campaign fundraisers, and searched two homes linked to his director of Asian affairs.

Adams has denied any knowledge of wrongdoing.

Adams said an interim replacement for Zornberg would be announced in the coming days.

“We appreciate all the work Lisa has done for our administration and, more importantly, the city over the past 13 months,” Adams said in a statement. “These are hard jobs and we don’t expect anyone to stay in them forever. We wish Lisa all the best in her future endeavors.”