A D.C. police officer illegally seized a camera phone from a citizen trying to photograph officers at the scene of an arrest, a civil liberties group alleged in a federal lawsuit filed Wednesday.

The ACLU filed the suit on behalf of the camera phone’s owner, Earl Staley Jr., a District resident, whose phone was taken by an officer just a day after the Police Department had issued a new directive prohibiting officers from seizing such devices or from interfering with citizens taking photos of police in public spaces.

Officers later returned the phone, but it was missing its memory card, which contained a trove of Staley’s personal photographs and other records, the suit says.

“When a police officer sees a camera he should smile,” Arthur B. Spitzer, legal director of the ACLU of the Nation’s Capital and the attorney representing Staley, said in a statement. “Officers must learn that people have a right to photograph them in public places, and that trying to cover up police misconduct is worse than the initial misconduct. The officer’s actions here will have consequences.”

D.C. Police spokeswoman Gwendolyn Crump referred calls to the office of the District’s attorney general. Ted Gest, a spokesman for that office, said in an e-mail that “we’re reviewing the lawsuit but will have no immediate comment on it.”

The lawsuit alleges that Staley was walking to a bus stop with a friend at 6 p.m. July 20 near the corner of Raleigh Street and Martin Luther King Jr. Avenue in Southeast when he saw a D.C. police car hit a man on a motorbike. Two police officers then began to punch the motorbike rider, who was on the ground and appeared to be hurt, the suit alleges.

Staley whipped out his smartphone, but by the time he was ready to snap a photograph, the confrontation was over. Two other officers appeared and began to aggressively shoo away bystanders, the suit says, one even “chest bumping” spectators.

Staley was about to photograph that officer when Officer James E. O’Bannon snatched his phone, the suit alleges.

The suit states that Staley asked O’Bannon to return his phone, but the officer refused, saying it might contain evidence of a crime. Another officer, Kenneth Dean, told Staley — incorrectly — that he had broken the law by taking a photograph of the officer in a public space, according to the suit. O’Bannon and Dean could not be reached for comment.

Later, at the 7th Police District station, a supervisor returned the phone to Staley. However, the suit says, the device was missing its memory card, which Staley had been using since 2008.

The incident came one day after D.C. police issued a new general order that prohibits officers from interfering with citizens who are photographing or recording police conduct in public. If police believe someone has images that might be evidence, officers may ask the person to send them the pictures or videos. If such a request fails, police may seek a judicial warrant to seize the camera or recordings.