My colleague Peter Rothberg flagged an important plea this morning: a group of community activists wants a full, independent investigation from the Justice Department into the NYPD’s treatment of Occupy Wall Street protesters. Just this weekend, many people reported excessive use of force at a demonstration in Zuccotti Park and many disturbing incidents were caught on film.

But Attorney General Eric Holder will receive another letter today asking for an investigation of the NYPD: this one, signed by over 110 Muslim, faith and civil rights groups, demands an investigation into the police department’s covert surveillance of Muslim groups inside and outside of New York.

The letter, signed by Muslim Advocates, the NAACP of New York and others, notes that since the surveillance spanned several states—and since New York authorities have refused to investigate—it’s the federal government’s job to lead a comprehensive investigation:

In light of the failure of state and local officials to act in response to the NYPD’s abusive conduct, it is critically important that the federal government vindicate our society’s commitment to equal justice under the law and the prohibitions against targeting communities and individuals based solely on their religion, ethnicity, or national origin. We strongly urge the Civil Rights Division to commence an immediate investigation of the NYPD’s past and current practices to identify whether it has violated, or continues to violate, the Constitutional, federal or state law rights of Muslims, including their rights to equal protection of the law, free exercise, and association.

Potentially illegal surveillance, with taxpayer funds, are a common thread in both investigations—and Occupy Wall Street also signed the letter demanding an investigation into the Muslim surveillance.

The Nation called for an investigation into this matter two weeks ago, as has the ACLU. You can see our action page here.