SAN DIEGO -- The San Diego Police Department is investigating a death that may have been related to a Taser gun, 10News reported.

Police say a "very violent" man, who was likely high on drugs and alcohol, refused to cooperate and officers shot him twice with a Taser gun. He was sent to the hospital and died two days later.

An investigation is under way but San Diego Police Chief William Lansdowne said that in 15 years, this is San Diego's first fatality connected in any way to the use of a Taser.

"You have to be very careful how you use them. You have to be able to be in a position to render immediate first aid -- all of that was done in this case," Lansdowne said.

More law enforcement agencies are using the Taser as an alternative. They say it cuts down on the number of deaths, however, some question those figures.

Mike Marrinan from the American Civil Liberties Union said, "I've seen many cases where a Taser was absolutely not called for."

The ACLU has not lodged a complaint about this case but cites cases such as one in Miami where shot two children under 12 with a Taser gun.

"I think the message ought to be to law enforcement -- this is a last resort. This is something that should only be used as an alternative to deadly force."

Lansdowne said officers value the sanctity of life and save it when they can. But the department has to balance that with looking out for its own.

Amnesty International is calling for a halt on the use of Tasers until the issue can be fully researched.

Lansdowne said they won't know the full truth of this incident until the autopsy report is complete, including toxicology reports, and that could take another three weeks.