A black teenage girl is suing a white police officer for assaulting her in a car park.

17-year-old Monique Tillman, then 15, was cycling through the car park of Tacoma Mall, Washington, with her brother Eric Branch, when they were stopped by an off-duty officer who was also a mall security guard.

He is seen on CCTV footage getting out his car and taking notes.

When Ms Tillman starts to cycle away, he grabs her off her bike.

“I tried to ride away, he grabbed me, threw me against someone's car, started choking me, grabbed me by my hair, and tried to slam my face into the concrete,” said Ms Tillman to King 5 News.

According to a court document filed by Ms Tillman’s lawyer, the off-duty officer stopped the siblings as they were “trespassing” in the car park, “causing a disturbance” and were carrying out “disruptive behaviour”.

Ferguson Anniversary Protests Show all 11 1 /11 Ferguson Anniversary Protests Ferguson Anniversary Protests Ferguson Anniversary Protests Police take a mug shot of a protester who was detained in Ferguson, Missouri, August 10, 2015. Protesters regrouped in Ferguson, Missouri, on Monday evening after a state of emergency was declared, aimed at preventing a repeat of violence the night before on the anniversary of the police shooting of unarmed black man Michael Brown. Ferguson Anniversary Protests Ferguson Anniversary Protests St Louis County police officers arrest an anti-police demonstrator in Ferguson, Missouri August 11, 2015 Ferguson Anniversary Protests Ferguson Anniversary Protests Protesters march in the rain, Sunday, Aug. 9, 2015, in Ferguson, Mo. Sunday marks one year since Michael Brown was shot and killed by Ferguson Police Officer Darren Wilson. Ferguson Anniversary Protests Ferguson Anniversary Protests Demonstrators, marking the one-year anniversary of the shooting of Michael Brown, march along West Florrisant Street in a driving rain on August 9, 2015 in Ferguson, Missouri. There are reports that two people were shot when gun fire broke out during protests later in the evening. Brown was shot and killed by a Ferguson police officer on August 9, 2014. His death sparked months of sometimes violent protests in Ferguson and drew nationwide focus on police treatment of black offenders. Ferguson Anniversary Protests Ferguson Anniversary Protests A St. Louis County police officers respond in an MRAD vehicle after shots were fired during a protest march on August 9, 2015 on West Florissant Avenue in Ferguson, Missouri. Over 50 shots were reportedly exchanged on the day marking the one year anniversary of the death of an unarmed black teen, Michael Brown, who was shot and killed by a white police officer, throwing America's troubled race relations into harsh relief. Ferguson Anniversary Protests Ferguson Anniversary Protests Protesters yell as police form a line across West Florissant Ave., Sunday, Aug. 9, 2015, in Ferguson, Mo., before shots were fired near the protest. The one-year anniversary of Michael Brown's death in Ferguson began with a march in his honor and ended with a protest that was interrupted by gunfire. Ferguson Anniversary Protests Ferguson Anniversary Protests Protesters fall to the ground to take cover after shots were fired in a police-officer involved shooting in Ferguson, Missouri August 9, 2015. Two people were shot in the midst of a late-night confrontation between riot police and protesters, after a day of peaceful events commemorating the fatal shooting of Michael Brown by a white officer one year ago. Ferguson Anniversary Protests Ferguson Anniversary Protests A white woman holds a black woman as they pray during a rain storm at the site of last year's riots on the one year anniversary of the killing of Michael Brown in Ferguson, Missouri August 9, 2015. Hundreds of people marched, prayed and observed a moment of silence in Ferguson, Missouri, on Sunday, a year to the day after a white police officer shot the unarmed black teenager to death, igniting months of protests and a national debate on race and justice. Ferguson Anniversary Protests Ferguson Anniversary Protests A woman reacts after shots were fired in a police-officer involved shooting in Ferguson, Missouri August 9, 2015. Two people were shot in the midst of a late-night confrontation between riot police and protesters, after a day of peaceful events commemorating the fatal shooting of Michael Brown by a white officer one year ago. Ferguson Anniversary Protests Ferguson Anniversary Protests Police take cover as a barrage of gunfire erupts along West Florrisant Street during a demonstration to mark the 1-year anniversary of the shooting of Michael Brown on August 9, 2015 in Ferguson, Missouri. Brown was shot and killed by a Ferguson police officer on August 9, 2014. His death sparked months of sometimes violent protests in Ferguson and drew nationwide focus on police treatment of black offenders. Ferguson Anniversary Protests Ferguson Anniversary Protests Amarion Allen, 11-years-old stands in front of a police line shortly before shots were fired in a police-officer involved shooting in Ferguson, Missouri August 9, 2015. Two people were shot in the midst of a late-night confrontation between riot police and protesters, after a day of peaceful events commemorating the fatal shooting of Michael Brown by a white officer one year ago.

Her older brother was kept back by another security officer while Ms Tillman was being tased.

“There’s no crime, we’re not doing anything, we’re just riding our bikes, really, through the mall to take a shortcut home,” said Mr Branch.

“That was not police-like,” he added. “They’re supposed to serve and protect us.”

Ms Tillman was arrested in the car park but the charges were later dropped.

Two years later Ms Tillman has decided to sue as she said they were doing “nothing wrong” and that the officer “just started harassing us”.

“I think it was more racially motivated because I feel like if we were two white kids, they wouldn’t have stopped us. They wouldn’t have said anything to us,” said Ms Tillman.

Ms Tillman is suing the off-duty officer, the Simon Property Group, the company that owns the mall, and Universal Protection Services for damages.