DALLAS — A woman alleges that police in the Dallas suburb of Arlington offered to drop charges against her two teenage sons in exchange for cellphone video she shot that she says shows an officer needlessly pushing her older son to the ground and arresting him.

At a news conference Thursday, Latasha Nelson said two police officers told her that they would give back her cellphone, which she says was illegally seized during the July 3 incident, after she surrendered the video. Her attorney, Kim T. Cole, said the officers insinuated that the charges against Nelson’s sons would be dropped if she agreed.

The Next Generation Action Network, a Dallas-based group that lobbies against police violence, posted the video on its Facebook page Wednesday on behalf of Nelson. A spokesman for the group, Dominique Alexander, said Nelson’s phone was backed up to the cloud, which enabled her to let the group post the video.

Cole, who is also an attorney for the action network, said the family wants the arresting officer, Chad Haning, to be fired and charged with official oppression. It also wants the charges to be dropped against the two boys and for any property to be returned, including Nelson’s phone.

“This video is full of violations of police policy. … They also unlawfully seized Ms. Nelson’s telephone. It is not illegal to film a police officer in this state,” Cole said, adding the officer threatened to arrest her if she didn’t turn over the phone.

“We’ve seen this repeatedly, not just locally but across the country, these young black men gunned down by police with impunity. … She was terrified, and yes, she was rightfully emotional.”

In an email, police spokeswoman Sgt. VaNessa Harrison said officers went to the family’s apartment complex because someone reported that there were two teens breaking into a car. She said the officers stopped Nelson’s 14-year-old son to question him because he fit the description of one of the teens being sought.

“The video starts at this point and shows two officers taking a teenager into custody. After reviewing the video, there are many questions that will require a thorough investigation,” Harrison wrote, adding that the officer remains on duty.

The video shows police walking the 14-year-old to a police car. Nelson can be heard asking where the officers are taking her son. A male officer, who later identifies himself as Haning, responds by saying he won’t tell her because she has “become uncooperative.”

It doesn’t show what led Haning, moments later, to engage Nelson’s 16-year-old son and put him on the ground because the video was zoomed in on Haning’s chest at the time. Nelson said Haning grabbed her older son by his face, knocking off his glasses before he pushed him to the ground to handcuff him.

“I am a black woman in America, and I love my kids. Do you know how hard it is to have four sons and think every day what could happen to them going out there in the world?” Nelson said.

Cole said a burglary charge against the 14-year-old and an obstruction charge against the 16-year-old were “pending investigation.”

Nelson said she filed a use of force complaint against Haning, but felt like it wasn’t taken seriously by the officers she talked to. She said she also received notice that the apartment complex was terminating her lease when it expires in October and told her she cannot appeal the decision.

The Associated Press filed a request Thursday for Haning’s personnel file, which wasn’t immediately available.