NEW YORK (CBSNewYork) — New York City’s Department of Investigation is accusing the Department of Correction of “unauthorized surveillance” of DOI investigators.

In a statement Monday, DOI Commissioner Mark Peters said DOC staff and Deputy Commissioner for the Investigation Division and Correction Intelligence Bureau Gregory Kuczinski eavesdropped on phones calls between the DOI and “confidential informants.”

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The alleged spying occurred “over a period of months this year” and “city rules expressly prohibit surveillance by DOC of calls made to DOI investigators,” Peters said.

“DOI’s investigation demonstrated that this was not inadvertent, but that DOC staff deliberately targeted DOI investigators for surveillance, and that they continued the surveillance even after written directives that such surveillance was to end,” Peters said. “There was a renewal of this activity, directed by DC Kuczinski, immediately after he and other senior staff were informed that DOI was preparing a report on their improper use of city vehicles.”

Last week, the DOI accused embattled Correction Commissioner Joseph Ponte, Kuczinski and other top correction officials of using their city cars to take personal trips out of town.

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Peters said Monday that he sent a letter to Mayor Bill de Blasio telling him about the alleged spying and demanding Kuczinski be removed, among other recommendations.

He said the mayor has agreed with all the recommendations, but a spokesman for de Blasio said Kuczinski has not been terminated. Instead, he has “been relieved from his investigation and call-monitoring responsibilities.”

Correction officials, including Ponte, told the New York Times there was no intent to interfere with a DOI probe, WCBS 880’s Rich Lamb reported. Kuczinski also denies any wrongdoing, 1010 WINS reported.

The DOI has been investigating allegations of brutality at Rikers Island. In March, the mayor said he wants to see the jail closed within the next 10 years.

Days later, a federal report blasted the jail, saying it continues to use excessive force at an “alarming rate.”

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“I want to thank City Hall for taking this issue of improper surveillance by DOC seriously and for acting quickly to resolve the problems,” Peters said Monday. “Interference, by anyone, with a DOI investigation is a very serious matter that will not be tolerated. In particular, surveillance of DOI activities in the city’s jails by the very agency DOI is investigating, not only compromises investigations but can potentially put the lives of investigators, correction officers, inmates and others at risk.”