DALLAS — Dallas police officers have been receiving death threats after body camera footage showing a controversial in-custody death was made public and went viral this week. 

Now department officials have warned officers to be careful. 

Acting Dallas Police Chief David Pughes sent out a safety bulletin to all officers encouraging them to ride in two-man units.

The video released this week shows the in-custody death of Tony Timpa in August of 2016. 

His mother says officers on the scene acted inappropriately.

"Why did they laugh at my son when he was begging for help. Why?" said Vicki Timpa.

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At the time, Timpa called 911 for help saying he was a schizophrenic, was off his prescriptions, and that he had taken cocaine. 

In the video, which was obtained by WFAA Thursday night, you can hear an unarmed Timpa saying, "you're going to kill me!" to Dallas officers who respond to his call for help. 

In the video, Timpa is hysterical. He's already been handcuffed by security guards from a nearby store and after rolling around on the ground--he's quickly restrained. 

As he's restrained, officers replace the security guard's handcuffs with some belonging to an officer. 

Timpa's feet are also tied together. 

For around 14 minutes, he's restrained by officers with their hands, and with their knees in the scapula area of Timpa's back. 

Timpa continues to cry for help saying that he's going to die. His face is buried into the ground, and his speech eventually becomes garbled. 

In the background, officers can be heard laughing. 

Eventually, Timpa falls unconscious. 

One officer can then be seen patting Timpa saying, "It's time for school, wake up!" 

Another officer chimes in a degrading voice and mocks, "But I don't want to go to school! Five more minutes, mom!" 

The group can then be heard talking about making Timpa breakfast, that there are waffles for him if he wakes up, etc. 

A paramedic then gives Timpa a sedative drug. 

But when he's placed on a gurney and appears lifeless, one officer says, "I hope I didn't kill him." 

Within minutes, body camera footage shows officers performing CPR on Timpa until he's declared dead by a paramedic.

An autopsy eventually found that Timpa had a cardiac death due to the toxic effects of cocaine and stress associated with physical restraint. 

Geoff Henley, an attorney representing Timpa's family in a federal lawsuit against the City of Dallas, said that the officers knew Timpa was on something and that they shouldn't have restrained him for that long. 

"From this radically prone position, Tony is going to suffer from asphyxia," Henley said. 

"When you're on a drug like cocaine, your heart is racing, you're not getting oxygen to the blood, and it creates this deadly cocktail."

The video sparked an outcry from the community and death threats against Dallas police officers. Many of those threats were posted on the Dallas Police Department's Facebook page.

"So why aren't Texans killing Dallas cops?" one man wrote. 

Another post says "I hope every pig involved in murdering that schizophrenic man dies a slow agonizing death. I will laugh.”

Three officers were indicted on misdemeanor deadly conduct charges but those charges were dismissed this year by Dallas County District Attorney John Creuzot. 

The release of the video was primarily sparked by the charges being dropped. 

Creuzot said three medical examiners declined to testify in the case. 

"In our opinion, there was no crime committed and there was no case to go forward,” said Creuzot.

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Now that the body camera footage has gone viral, Dallas police are worried about the threats. 

"There are death threats right now. That's what they are calling for. 'Kill these officers,'" said Richard Santiesteban of the National Latino Law Enforcement Organizations-Greater Dallas.

"Of course we are worried," he said. "It's alarming and it's disturbing."

Henley told WFAA that he wants to get, "court justice, and not street justice." 

He asked that people don't take matters into their own hands, and to write their city councilperson or the Dallas Police chief if they're upset. 

But Henley also argues that the body camera footage should have been released long ago, he adds that it was made confidential during the criminal proceedings of the three officers. 

"The public has a right to know what takes place on a public road," Henley said. "People pay taxes, and we definitely need to see these things." 

Timpa's mother Vicki will address the video in a press conference on Friday.