MADISON, Wis. -

To say Brian Landers knows about tasers is an understatement. The criminal justice chair for Madison College, Landers teaches future officers how and when to use the weapons out in the field.

Landers said Tasers can be very effective tools for police, but if Tasers are employed against an armed person, there should definitely be backup.

“The taser could potentially be used to try and stop advancing their threats,” Landers said. “But that should only be used when the officer has lethal cover, meaning that a secondary officer is prepared to use deadly force when needed.”

Madison Police were called to 5214 Hammersley Road for reports of a husband stabbing his wife in the stomach. Three officers confronted the man, identified as 59-year-old Charles Carll, in the back yard. Police said Carll still had a knife and was suicidal.

Madison Police spokesperson Joel DeSpain said Carll advanced toward the officers who were yelling verbal commands to drop his weapon. They attempted to use a Taser on Carll, but when he kept approaching them, deadly force was used.

DeSpain said they’re still looking into how many shots were fired. All three of those officers Alex Bol, Adrian Alan, and Ed Marshall are on paid administrative leave pending the outcome of the internal investigation.

Requests for the 911 call and the dash-camera video from Saturday’s shooting were denied.

Landers said a number of things can go wrong to render a Taser ineffective. He mentioned the environment --the wind, for instance-- a person’s clothing, and an equipment malfunction can all affect the outcome.

Depending on the model, Tasers are only meant to shoot probes 15 feet to 25 feet, and it can be difficult to hit a person in the optimal location and bring them to the ground. In addition, Landers said some people don’t react to the electric pulses.

“Even though the muscular disruption that occurs, the large muscle groups, you can still move. Not much, but you can still move, and if they can move enough just to try to dislodge one of these, then its pain. That's all it is,” Landers said. “It's no longer that muscle lockup, it's just pain. And a lot of people can override pain.”

Overall, Landers said police need a number of options out in the field to protect themselves and their colleagues.

“The best tool, the best weapon that they have is their minds and their mouths and their hands and their feet. That's the best weapon that a police officer has,” Landers said