NEW YORK (CBSNewYork) — In a sudden and surprising development Friday, Department of Investigation Commissioner Mark Peters is stepping aside in the New York municipal corruption investigation.

As CBS2 Political Reporter Marcia Kramer reported, the DOI announced late Friday afternoon that Peters as recusing himself from the federal investigation, which focuses on the NYPD and Mayor Bill de Blasio’s fundraising.

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On Thursday, Peters said there was no reason to recuse himself, Kramer reported. But a day later, he decided to step aside as his department participates in the ongoing the sprawling probe, so as “to avoid the appearance of conflict.”

Peters was treasurer for de Blasio’s 2013 campaign. In his remarks Thursday, he said he did not have to stop participating in the investigation because his fundraising activities ended when Mayor de Blasio took office.

It came just after de Blasio reversed course himself. Initially, he said he did not need an attorney after the feds started questioning members of the real estate industry about his campaign’s fundraising activities.

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But earlier this week, de Blasio turned around and hired Barry Berke, one of the foremost criminal defense attorneys in the country.

He said Tuesday that he had asked Berke to “reach out to the U.S. Attorney’s office and offer any assistance he could provide. We’re happy to work with them in any way that would be helpful.”

Berke represented former police Commissioner Bernard Kerik in his federal fraud case.

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Sources said the DOI will continue to participate in the federal probe, but Peters will not be briefed about the progress of the probe, the targets, and how the case is developing.