ST. LOUIS, MO - AUGUST 12: A tear rolls down the cheek of Lesley McSpadden, the mother of slain teenager Michael Brown, during a community meeting held at Greater St. Marks Family Church to discuss the killing of her son and the civil unrest resulting from his death on August 12, 2014 in St Louis, Missouri. Brown was shot and killed by a police officer on Saturday in the nearby suburb of Ferguson. Ferguson has experienced two days of violent protests since the killing but, tonight the town remained mostly peaceful. (Photo by Scott Olson/Getty Images)

WASHINGTON -- The American Civil Liberties Union of Missouri filed formal requests on Tuesday to obtain a copy of the police incident report naming the officer who shot Michael Brown, the unarmed black teenager killed Saturday while walking down the street in a St. Louis suburb.

The ACLU submitted its requests to the Ferguson Police Department and the St. Louis County Police Department. Both were filed under the state's Sunshine Law, which stipulates that records of public governmental bodies be made open to the public.

Diane Balogh, communications director for the ACLU of Missouri, said the group filed the requests specifically to find out the identity of the police officer. The Ferguson Police Department originally planned to release the officer's name on Tuesday, but then decided not to, citing threats against the officer. In the meantime, the Justice Department is overseeing an investigation into the shooting and Ferguson has become a scene of daily protests and vandalism, with police even using tear gas on people standing in their own backyards.

"If they don't follow through, we will file a lawsuit and hold a press conference," Balogh told The Huffington Post. "There have been other situations where we've actually had to sue the police department because they haven't fulfilled the Sunshine Law requirements."

She added, "The police like their secrets."

Missouri's Sunshine Law specifies that requests for information be acted on as soon as possible, but "no later than the end of the third business day following the date the request is received."

Requests for comment from the Ferguson Police Department and the St. Louis County Police Department were not immediately returned.