The woman, whose name we have withheld pending a response from the NYPD, being detained by three plainclothes officers yesterday in Union Square (Jessica Lehrman / Gothamist)

Shortly after yesterday's May Day rally in Union Square, we witnessed what we could only assume were three plainclothes NYPD officers detain a woman and search her bag, before leading her through the crowd and into police custody. Several times the officers are asked to identify themselves, and refuse. According to the NYCLU's Associate Legal Director Christopher Dunn, plainclothes officers must identify themselves by name, rank, and shield number upon request, per the department's patrol guide.

The NYPD's Deputy Commissioner Paul Browne tells us via email, "Police have no obligation to identity [sic] themselves to bystanders and certainly not to anyone attempting to interfere with an arrest."

Dunn responds via email, “Apparently Paul Browne is unfamiliar with the Department’s Patrol Guide which expressly requires police officers to identify themselves when asked."

Gideon Oliver, president of the National Lawyer's Guild—New York City Chapter says, "Plainclothes officers should certainly be identifying themselves if they're engaged in detaining someone or performing the same duties that a uniformed officer would, especially to the person they're detaining."

This makes sense: if plainclothes police officers are not under any obligation to identify themselves, what's to stop any group of men from detaining anyone under a false pretense of being a police officer? Just this morning, the NYPD sent out a press alert regarding Julian Rodriguez, a 25-year-old man who is wanted in connection to an incident in which two men claiming to be police officers gained entry to an apartment in Jackson Heights before 5 p.m. on Friday. Once inside, the men, armed with switchblades, robbed the victim before fleeing.

Oliver continues, "Paul Browne seems to be using the slippage between the terms 'plainclothes' and 'undercover,' but if you're talking about arresting someone in broad daylight—absolutely they should be identifying themselves. It's no different than any other officer performing their duties."

We witnessed several plainclothes officers making arrests yesterday, with one detaining a protester who was attempting to tamper with the undercarriage of a bus during the Wil... and another participating in the violent arrest of several protesters after they stepped onto the street at Sixth Avenue and Waverly. That officer had just moments before been marching with a group of several hundred protesters west on Waverly from Washington Square Park.

[UPDATE] Deputy Commissioner Browne emails us to say that the woman, Kathryn Robinson, was charged with criminal possession of stolen property and petit larceny. We're attempting to contact Robinson to get her take on the arrest.