A teenager died after being hit with a police Taser gun for 37 seconds, and the whole thing was caught on tape by surveillance cameras.

Authorities said that Darryl Turner had been in a confrontation with a supervisor at work at a North Carolina grocery store. When Officer Jerry Dawson arrived, he fired his Taser gun at the 17-year-old and struck him in the sternum.

"The initial use of the (Taser gun) is not in question," said Charlotte-Mecklenburg police Chief Ken Miller.

However, for 37 seconds, Dawson continued to use the Taser gun against the teen. An autopsy revealed that Darryl Turner died of a heart attack, authorities said.

NBC Charlotte affiliate WCNC reported that Dawson was given a five-day suspension for firing the Taser gun too long.

"I wouldn't want to be (hit with a Taser gun) for 37 seconds, I can assure you of that," said Joe Kuhns, a professor of criminal justice at the University of North Carolina at Charlotte. "It's a lengthy period of time."

Kuhns said he does support the use of the guns, however. "For the most part, their use has been effective. It has reduced officer injuries. It has reduced suspect injuries."

But a recently released National Institute of Justice study indicated that since 1987, there have been 300 deaths from the devices, also called conducted energy devices.

"There may be circumstances in which repeated or continuous exposure is required, but law enforcement should be aware that the associated risks are unknown," the study said. "Therefore, caution is urged in using multiple activations of (Taser guns) as a means to accomplish subdual."

Turner's family said they believe he didn't have to die.

"The officer was not confronted with circumstances that required the use of that type of force," said family attorney Ken Harris.

Dawson won't face criminal charges in the case, but Turner's family is considering a lawsuit, WCNC reported.