Authorities in Texas are investigating allegations surrounding cell phone footage of police officers using force against a pregnant woman accused of prostitution.

San Antonio police officers approached Destiny Rios around 4:30 p.m. on July 4. A background check revealed that the 21-year-old -- who is 5'1, 126 pounds and approximately three months pregnant -- had an outstanding warrant for prostitution, so authorities began to arrest her.

Some are calling the ensuing incident an act of police brutality.

Lorenzo Rios, who has no known relation to the victim, recorded the incident on a cell phone camera from across the street.

"She didn't put up a fight, she just said, 'Stop choking me, I'm pregnant,'" the 18-year-old told KENS-5. "You could hear from across the street the pounding on her back and on her bones and she was yelling to stop because she was pregnant."

Rios said that police slammed the woman on the police cruiser hood, causing her to start "squirming to get away," the witness said.

San Antonio Police Chief William McManus said that authorities are reviewing the incident, but at this point they do not believe there was foul play.

"Based on what we know right now, there was no reason to put them on admin duty," said Chief McManus. "We are going to look into it further though, just to make sure all our policies and procedures were followed properly."

Destiny Rios used heroin the day before the incident, KABB reports. Police arrested her for prostitution and resisting arrest.