ST. LOUIS — Two documentary filmmakers are suing the city of St. Louis and three police officers, saying one of them was cursed at and beaten and they were both sprayed with chemicals when they were arrested during a protest following the acquittal of a white former police officer in the killing of a black man.

Drew and Jennifer Burbridge of Kansas City, Missouri, filed the federal lawsuit Tuesday, alleging their constitutional rights were violated when they were arrested, taunted and assaulted by St. Louis officers.

Koran Addo, a spokesman for St. Louis Mayor Lyda Krewson, declined comment Thursday.

The Burbridges were among about 120 people taken into custody in a mass arrest on Sept. 17, two days after a judge ruled that Jason Stockley was not guilty of first-degree murder in the 2011 death of Anthony Lamar Smith. The ruling sparked several protests throughout the St. Louis region.

The Sept. 17 protest turned unruly when some demonstrators hurled items at police and broke downtown windows. Police used a process known as “kettling,” in which lines of officers move protesters into a limited area. Police said when they ordered the crowd to disperse and that those who failed to comply were arrested.

The Burbridges’ lawsuit says they didn’t hear an order to disperse and that when police began to converge, they wanted to leave but were blocked in. The suit says police would not allow them to leave.

Police sprayed both with chemical agents, the suit says, and Drew Burbridge was thrown to the pavement, face first.

Officers “proceeded to strike him on the ankles, legs, body, and head, with their feet, hands, and batons,” the lawsuit said. “While beating Drew Burbridge, one of the John Doe Defendants stated: ‘Do you want to take my picture now (expletive)? Do you want me to pose for you?'”

The lawsuit said Drew Burbridge lost consciousness, awaking “to an officer pulling his head up by his hair and spraying him with chemical agents in the face.”

The lawsuit, which seeks unspecified damages, alleges they were targeted for arrest because they are journalists.

The Sept. 17 arrests have already drawn significant complaints, including a lawsuit from the American Civil Liberties Union of Missouri, alleging that police were too forceful, taunted those being arrested, and arrested innocent bystanders. Krewson and Interim Police Chief Lawrence O’Toole on Wednesday announced that they were asking the U.S. attorney’s office to conduct an independent investigation.

U.S. Rep. William Lacy Clay also wants an independent investigation into recent St. Louis County arrests.

The St. Louis Democrat sent a letter Thursday to County Executive Steve Stenger and County Council Chairman Sam Page, urging an “independent and impartial” investigation of the arrests of 22 people on Saturday at the St. Louis Galleria shopping mall in Richmond Heights, Missouri.

“The first-hand and video accounts of citizens who were subjected to brutal treatment, arrest, prolonged detention, and alleged deprivation of medical care are chilling and outrageous,” Clay wrote.

St. Louis County and Richmond Heights police said the arrests were necessary when protesters became unruly, blocked escalators and tried to go to the mall’s second floor, against the wishes of mall management. But protest leaders and some elected officials have called the incident a “police riot.”