City spokeswoman Anna Clark identified the officer as 41-year-old David Eric Casebolt, who joined the police force in August 2005.

Prior to that, he served almost two years as a state trooper, according to records from the Texas Commission on Law Enforcement.

Casebolt took eight hours of cultural diversity training at Collin County Community College in February 2009. He has also taken courses in racial profiling and use of force.

As police broke up the crowd, the officer pulled the bikini-clad girl to the ground, then used his knees to pin her down. He also pointed his gun at other teens and cursed.

The girl claimed the officer told her to walk away but forced her down after "he thought we were saying rude stuff to him,'' according to an interview she gave to television station KDFW.

"He grabbed me, twisted my arm on my back and shoved me in the grass and started pulling the back of my braids,'' Dajerria Becton, 15, told the station. "I was telling him to get off me because my back was hurting bad.''

"I understand how he was feeling, everybody surrounding him,'' she said. "I don't think he should have pulled a gun out on 15-year-old kids.''

Brandon Brooks, the teen who recorded the video, told KDFW that tensions rose after a white woman and a black teenager at the party had an altercation. He said the white woman told the teen "to go back to Section 8 housing,'' a reference to federal housing aid given to low-income families.

The comment holds extra significance in McKinney, which has been the target of lawsuits accusing its housing authority of racially segregating Section 8 housing. One long-running lawsuit was settled with a consent decree in 2012 that aimed to open up the predominantly white west side to subsidized housing.

Brooks said that the officer was "out of line'' and that he felt compelled to keep filming when Casebolt pulled out his gun.

"At that point, my heart did drop and I was scared that someone was going to get shot and possibly killed,'' he said.

McKinney Mayor Brian Loughmiller said city officials plan to meet with community leaders to discuss the incident.

"We really need to come together as a community,'' the mayor said.

Most people were released, except for one man arrested for interference with the duties of a police officer and evading arrest, police said.