From Snopes:


Kerry earned his Silver Star on 28
February 1969, when he beached his craft and jumped off it with an M-16 rifle
in hand to chase and shoot a guerrilla who was running into position to launch
a B-40 rocket at Kerry's boat. Contrary to the account quoted above, Kerry did
not shoot a "Charlie" who had "fired at the boat and missed," whose "rocket
launcher was empty," and who was "already dead or dying" after being "knocked
down with a .50 caliber round." Kerry's boat had been hit by a rocket fired by
someone else — the guerrilla in question was still armed with a live B-40 and
had only been clipped in the leg; when the guerrilla got up to run, Kerry
assumed he was getting into position to launch a rocket and shot him:

On Feb. 28, 1969, Kerry's boat received word that a swift boat was being
ambushed. As Kerry raced to the scene, his boat became another target, as a
Viet Cong B-40 rocket blast shattered a window. Kerry could have ordered his
crew to hit the enemy and run. But the skipper had a more aggressive reaction
in mind. Beach the boat, Kerry ordered, and the craft's bow was quickly rammed
upon the shoreline. Out of the bush appeared a teenager in a loin cloth,
clutching a grenade launcher.

An enemy was just feet away, holding a weapon with enough firepower to blow up
the boat. Kerry's forward gunner, [Tommy] Belodeau, shot and clipped the Viet
Cong in the leg. Then Belodeau's gun jammed, according to other crewmates
(Belodeau died in 1997). [Michael] Medeiros tried to fire at the Viet Cong, but
he couldn't get a shot off.

In an interview, Kerry added a chilling detail.

"This guy could have dispatched us in a second, but for . . . I'll never be
able to explain, we were literally face to face, he with his B-40 rocket and us
in our boat, and he didn't pull the trigger. I would not be here today talking
to you if he had," Kerry recalled. "And Tommy clipped him, and he started going
[down.] I thought it was over."

Instead, the guerrilla got up and started running. "We've got to get him, make
sure he doesn't get behind the hut, and then we're in trouble," Kerry recalled.


So Kerry shot and killed the guerrilla. "I don't have a second's question about
that, nor does anybody who was with me," he said. "He was running away with a
live B-40, and, I thought, poised to turn around and fire it." Asked whether
that meant Kerry shot the guerrilla in the back, Kerry said, "No, absolutely
not. He was hurt, other guys were shooting from back, side, back. There is no,
there is not a scintilla of question in any person's mind who was there [that]
this guy was dangerous, he was a combatant, he had an armed weapon."
Another member of the crew confirmed Kerry's account for the Boston Globe and
expressed no doubt that Kerry's action had saved both the boat and its crew: