"As the bull approached, it attacked runners seeking refuge at the fence," said Roberto Sanz, 43, a veteran Pamplona runner who was near Jimeno Romero when he died but did not witness it.

Amateur video footage shows Jimeno Romero, wearing white pants and a brown-and-white striped shirt, trotting backward as he faced the oncoming bull and stumbling when other runners go down. He tried to squeeze under the fence, and was halfway there, when Capuchino caught him with a single swipe of his right horn.

Jimeno Romero began bleeding profusely and was tended to quickly by medics as he lay with his eyes half open.

Later, when Capuchino reached a stretch right outside the bullring, he started charging right and left, and ran back the wrong way several times. Runners sprinted to wooden barriers along the route for safety as the bull attacked. Herders tried in vain to guide him into the ring, yanking on the animal's tail to turn it around.

This went on for a minute and a half, which is an eternity at the San Fermin festival. Fast runs — the whole sprint — can end in just over two minutes.

At one point the bull picked one man up with its horns and flipped him into the air as if he were a toy, then kept going after him as he lay curled up on the ground, covering his face. He got up and ran away and was apparently not seriously hurt.

"It was a light bull. Its charges were not particularly strong, but it moved very fast from left to right," one of the bull herders, Humberto Miguel, told The Associated Press. "Of the whole pack, it was the one that gave us the most trouble."

The bulls used in Friday's run, from a ranch called Jandilla, have a reputation for being fierce at San Fermin. They hold the record for the most gorings in a single run — eight, one day in 2004.

The last fatal goring at the running of the bulls was that of 22-year-old American Matthew Tassio in 1995. Then, the problem was not a stray bull but a fatal mistake by Tassio: After falling, rather than stay on the ground and wait for the pack to pass over, he stood up and faced the animals. A bull's horn hit him right in the chest.

In 2003, a 63-year-old Spanish man, Fermin Etxeberri, was trampled in the head by a bull and died after spending months in a coma.

Fatalities are relatively rare and when one occurs, it serves as a reminder that amid all the street parties and revelry associated with San Fermin, running with fighting bulls is a life-risking exercise.