BALTIMORE COUNTY, Md. (WJZ) — Fighting for justice. The family of a teen killed by an off-duty Baltimore County police officer is calling for an independent investigation of the case.

Meghan McCorkell has more on their plight.

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The family of 17-year-old Christopher Brown is not happy with the manslaughter charges against the officer that killed their son. They’ve made it their mission to get murder charges in the case.

“I didn’t see this day coming. My son is not here today,” said his mother, Chris Brown. “He was a sweetheart. He was loving. He was kind.”

Brown died June 13 after a group of friends threw rocks at the front door of Officer James Laboard. Investigators say the off-duty officer chased Brown, dragged him out of bushes and a struggle ensued. Brown fell unconscious and died. The coroner ruled it homicide by asphyxiation. The officer was charged with manslaughter and released on his own recognizance–a move the Brown family calls an insult.

“There’s no way he should be walking the streets like this and I don’t have my son,” Brown said.

The family is now petitioning the State’s Attorney’s Office to file second-degree murder charges.

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Tuesday night, supporters gathered to rally around the family and sign that petition.

“We want second-degree murder. Nothing less!” said Marvin “Doc” Cheatham, National Action Network.

They’re also appealing to lawmakers to ban police officers from using any force that could restrict a person’s airway.

“I don’t care if it’s a chokehold or sleeper hold, bearhug–whatever can put you unconscious. We don’t want that to happen again,” said Brown family attorney Russell Neverdon.

Preventing another tragedy is now a lifelong mission for Brown’s mother.

“We’re hurting and we want justice for Christopher. I’m talking so no other life…nobody has to suffer like this,” she said.

The Brown family plans to meet with the State’s Attorney next week.

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The State’s Attorney’s Office tells WJZ there are no new developments in the case.