Maui police are investigating their use of a Taser stun gun in an incident in which a Kihei man fatally shot himself Tuesday night after officers tried to subdue him with the device.

Officers were responding to domestic dispute call at Kihei Villages apartment when they encountered the 49-year-old man, with semi-automatic pistol in his hand and his wife in the room, police said. Officers arrived at 1:05 a.m. Tuesday, police said.

After attempting to negotiate with the man for about 20 minutes, police used a Taser gun in an effort to subdue him. Despite the shock, the man was able to shoot himself in the head, police said.

He died at the scene.

Glenn Miyahira, Kihei patrol commander, said it was unclear whether the use of the Taser played a role in causing the man to shoot himself. "This will be fully investigated," Miyahira said.

In December, about two months after the Maui Police Department began using Tasers, police used a stun gun to stop a suicidal man from pulling a loaded 9mm pistol from his backpack in Kula.

Maui police are pursuing two investigations into the suicide, one by the department's Criminal Investigation Division detectives and the other by Internal Affairs investigators. The latter will evaluate procedures, policy, performance, training and equipment, including the Taser.

Dr. Linda Rosen, director of health resources administration for the state Department of Health, said she did not know whether Tasers had been studied as suicide-prevention tools.

Rosen, an emergency room physician, said when suicidal patients fail to respond to negotiations in an emergency room, they may be subdued with injected medication. She said the idea "that you could do that from a distance has some appeal."

"If I give you a tiny little wire shock your muscle may contract, but if I give you a really big shock your heart might stop and you'd collapse," she said. "I don't think anyone really knows for sure" whether Tasers are effective suicide-prevention tools.

A Taser can temporarily paralyze an individual with a 50,000-volt jolt delivered by two barbed darts that can penetrate clothing.

The uses of Tasers has come under scrutiny recently as civil-rights groups and some police agencies question the safety of stun guns. Honolulu and Maui police began using Tasers last year.

Reach Peter Boylan at pboylan@honoluluadvertiser.com.