When the Occupy protests spread across the country three years ago, state and local law enforcement officials went on alert. In Milwaukee, officials reported that a group intended to sing holiday carols at “an undisclosed location of ‘high visibility.’ ” In Tennessee, an intelligence analyst sought information about whether groups concerned with animals, war, abortion or the Earth had been involved in protests.

And in Washington, as officials braced for a tent encampment on the National Mall, their counterparts elsewhere sent along warnings: a link to a video of Kansas City activists who talked of occupying congressional offices and a tip that 15 to 20 protesters from Boston were en route. “None of the people are known to be troublemakers,” one official wrote in an email.

The communications, distributed by people working with counterterrorism and intelligence-sharing offices known as fusion centers, were among about 4,000 pages of unclassified emails and reports obtained through freedom of information requests by lawyers who represented Occupy participants and provided the documents to The New York Times. They offer details of the scrutiny in 2011 and 2012 by law enforcement officers, federal officials, security contractors, military employees and even people at a retail trade association. The monitoring appears similar to that conducted by F.B.I. counterterrorism officials, which was previously reported.