The Anonymous collective has posted documents that appear to contain the personal information of 1000 US police officers in Massachusetts and Alabama.
The group said it leaked the stolen data, which included the names, addresses, ranks, phone numbers and Social Security numbers for officers in Birmingham as part of the National Day of Protest to Stop Police Brutality.
The Twitter account "@anon260" was issuing the tweets containing links to Pastebin documents.
The other publicly posted document contained the names, usernames and passwords of more than 1000 members of the Boston Police Patrolmen's Association (BPPA).
Calls placed to both the Birmingham Police Department and BPPA were not immediately returned.
Today's commemoration included ground protests, as well, highlighted by a demonstration in Harlem against the New York City police's stop-and-frisk practices. The protest received support from the Occupy Wall Street movement. Thirty-two people were arrested, according to reports.