The suicidal 23-year-old man had a knife in each hand and was raising one above his head as he moved to within five feet of the Bedford County deputies.

Suddenly, he dropped both knives and collapsed to the floor of his mother's home, said Capt. Kevin Adams of the Bedford County Sheriff's Office.

By shocking the man with a Taser stun gun, a sheriff's deputy had removed a threat without having to riddle the man with bullets, Adams said.

"It's no doubt in my mind that it saved the young man's life," Adams said of the stun gun.

The event last year in the Forest area of Bedford County bears similarities to an incident last week in Roanoke involving a man who appeared suicidal and had armed himself with a samurai sword. He, like the man in Bedford County, was about 5 feet from a police officer and ignored commands to drop the weapon, police said.

But John Harvey Bridges, 43, was shot once in the torso with a gun. He died a few hours later.

That incident, and the recent fatal shooting by Roanoke police of another man who also had wielded a samurai-style sword, have prompted relatives of both men to question why authorities didn't use a Taser or some other nonlethal kind of force.

Underscoring these concerns is the fact that Roanoke police have shot three people this year, two fatally, and shot four people last year, one fatally.

The city's top prosecutor has determined, in some cases only as a preliminary finding, that six of the seven shootings were legally justified. He is awaiting investigative reports from Roanoke police before deciding on the Bridges case.

As to the question of why Roanoke police did not use a Taser to disable Bridges or Geoffrey Stephenson, who was armed with a sword and at least one gun when he was killed in February, the simplest answer is that officers do not carry them.

Police Chief Joe Gaskins declined to discuss his opinion of the controversial stun guns, saying he doesn't wish to sound critical of agencies that use them. A police department spokeswoman added that Gaskins is not considering them as an option.

Roanoke police officers do carry pepper spray and batons. Some also have access to shotguns that fire nonlethal beanbag rounds, but these weapons generally are used from at least 30 feet away and can be unwieldy in cramped quarters such as Bridges' apartment on Old Spanish Trail.

While some agencies praise Tasers for their nonlethal effectiveness, critics cite numerous reports nationwide of abuses by police officers. Some have called for moratoriums on their use.

Amnesty International said in March 2006 that Tasers used by police in the United States had been linked to 152 deaths since 2001 and that most of the incidents involved unarmed people who posed no serious threat to anyone.

Steve Tuttle, vice president of Taser International Inc., which sells the weapons, disputed Amnesty's findings. He conceded, however, that he knows of six cases in which medical examiners listed a Taser as a contributing factor to someone's death.

Roger Barr, a professor of biomedical engineering at Duke University, said he believes that the stun guns could fatally disrupt a regular heartbeat, especially in someone who has a weak heart or is using drugs.

"The problem here is we just don't know," Barr said, adding that Tasers would be a good alternative to using a gun but should not replace verbal persuasion or a milder show of force.

"I think it is more dangerous than most police would realize," he said.

Tasers send an electric current through barbed probes that catch in a person's skin or clothing, temporarily disabling them, Tuttle said. Some models can fire up to 35 feet.

More than 10,500 law enforcement agencies in the United States have Tasers, including about 255 in Virginia, Tuttle said. The weapons also are used in 44 other countries.

Most law enforcement agencies surrounding Roanoke don't use Tasers. The Roanoke County and Vinton police departments both are considering buying the weapons, which cost $400 to $800 apiece. Neither Salem police nor Botetourt County deputies carry them.

"They're controversial," said Botetourt sheriff's Maj. Delbert Dudding. "The rare occasion that you use it ... every now and then, somebody dies."

Virginia State Police troopers generally don't carry Tasers either, although members of the agency's tactical teams have them. But state police haven't zapped a suspect with a Taser since they got the weapons in 2004, said Sgt. Eric Penree of the agency's tactical operations unit.

In Bedford County, authorities have used Tasers 18 times since September 2004, Adams said. County deputies used other types of force 32 times over that period, with Tasers placing second to physical force, with 23 such incidents.

Pepper spray was used four times and a baton three times, and police dogs accounted for two of the uses of force.

The city of Bedford also has Tasers. The device has been used only once on an unarmed combative suspect, said police Capt. Stephen Rizzuto.

"Immediately, the situation was under control," Rizzuto said.

Authorities are quick to point out that every situation is different and that no police academy can teach officers how to handle every type of situation.

Bridges' sister in-law, Terry Bridges, said that his family wants to know why Roanoke police didn't just shoot Bridges in the legs.

Roanoke officers are trained to use deadly force as a last resort to "stop the threat," said Capt. Curtis Davis, a former director of the Roanoke Police Academy who also was a commander of the tactical team.

Davis noted that people who have been shot multiple times can go on to attack someone else.

"Television has misled a lot of people on the effects of firearms -- that and movies combined," Davis said. "There is no guarantee that a gunshot, even center mass, is immediately going to stop a suspect."