SPOKANE, Wash. -- Spokane Police responded to an incident Sunday night involving a man armed with a knife. When the man did not respond to verbal commands, police deployed a taser. The taser had no impact on the man, which prompted police to open fire.

“I don’t understand how the taser again isn’t affective. How the non-lethal option isn’t affective because we just experienced this back in January,” said witness Jay McPhee.

Sunday’s incident was the second officer-involved shooting this year involving a suspect with a knife. The first was in January near South Adams Street and West 9th Avenue.

In January, police said multiple officers were able to deploy taser, but they were ineffective.

After looking through past use of force incidents, KREM 2 discovered police cited several incidents where tasers were not effective. The Use of Force Report from the Spokane Police Department details several incidents where tasers did not work either.

The situation made KREM 2 ask: How effective are tasers?

Two on Your Side’s Lindsay Nadrich looked into it.

In some cases, officers said the suspect was under the influence of drugs, so the taser had no effect. In other cases, the taser did not work because the probes did not connect with the suspect.

According to police, tasers only work about half the time without any issues.

KREM 2 is still waiting on details from the police department about why the taser in Sunday’s incident was not enough. Three officers fired at the suspect a few seconds after the taser did not work.