The New York Police Department has secretly labeled entire mosques as terrorism organisations. The designation has allowed police to use informants to record sermons and spy on imams, often without specific evidence of criminal wrongdoing.
Since the 9/11 attacks, the NYPD has opened at least a dozen "terrorism enterprise investigations" into mosques. The TEI is a police tool intended to help investigate terrorist cells.
Designating an entire mosque as a terrorism enterprise means that anyone who attends prayer services is a potential subject of the investigation and fair game for surveillance. Many TEIs stretch for years, allowing surveillance to continue even though the NYPD has never criminally charged a mosque or Islamic organization with operating as a terrorism enterprise.
The NYPD declined to comment.