A Hummelstown, Pa., police officer employed a TASER on David Kassick Feb. 2, but ended up fatally shooting him after he didn't obey commands to show his hands. This week, Dauphin County District Attorney Ed Marsico announced she has been charged with homicide in Kassick's death.

"Clearly when they work properly, Tasers cause fewer and less severe injuries to subjects and officers both," said retired Los Angeles Capt. and POLICE Advisor Greg Meyer, who has 36 years' experience with Tasers and use of force issues.

But tazing a suspect doesn't always eliminate use of deadly force. In 2007-08, Meyer said he found 45 fatal police shootings in the U.S. and Canada after an officer had attempted to taze the suspect.

Meyer estimates that 8 to 10 percent of fatal shootings today involve an attempt to first taze the suspect, PennLive reports.