COLUMBUS, OHIO ? It looked like something out of a macabre heavy-metal video: The lights dimmed in the smoke-filled nightclub, the rock band Damageplan launched into its first thunderous riffs, and then a man in a hooded sweatshirt ran the length of the stage and opened fire, shooting the lead guitarist at least five times in the head.

In just minutes, the gunman had killed three others with his silver pistol before being shot to death by a police officer.

The rampage Wednesday night stunned the heavy metal world and left police searching for answers about what set the gunman off.

The slain guitarist, “Dimebag” Darrell Abbott, 38, was a driving force behind the rock band Pantera, and police are looking into reports from witnesses that the gunman was a fan irate that the hugely influential group broke up.

Some of the 500 people packed into the club to see Abbott’s new band initially thought that the gunman was an excited fan or that the shootings were part of the show.

“I figured it was another fan wanting to jump off the stage and crowd surf,” said Brian Kozicki, the club’s lighting designer. “I think he knew he wasn’t going to get out and he was going to take down as many people as he could.”

Police identified the gunman as Nathan Gale, 25, who listened to Pantera music to psyche himself up before football games and would often hang out at a tattoo parlor and make a pest of himself by talking to customers about music, the manager of the tattoo shop said.

“We may never know a motive for this, unless he left a note,” Sgt. Brent Mull said.

A tattoo artist at the studio, Bo Toler, said Gale was there before the show and asked about having the studio order tattoo equipment for him. Toler told him no, and Gale got angry and started yelling.

Lisa Cawthron, of Arlington, Texas, places flowers in front of the home of rock artist Dimebag Darrell Abbott, Thursday in Dalworthington Gardens, Texas. Abbott was killed Wednesday while performing in Columbus, Ohio. Cawthron said that she had known Abbott and other members of his family.

“Last night was actually the first time I noticed his temper,” Toler said. “After the argument we had he kind of walked out with an attitude. He didn’t even say goodbye.”

Also killed in the shootings were Erin Halk, 29, a club employee who loaded band equipment; fan Nathan Bray, 23; and Jeff Thompson, 40, who was affiliated with the band.

Two others were hospitalized. The nature of their injuries was not disclosed.

Lines were deep Wednesday night at the Alrosa Villa club — a popular venue for heavy metal for 30 years — to buy T-shirts for Damageplan.

As the lights dimmed, club security was trying to catch up to a man in a Columbus Blue Jackets hockey jersey over his sweatshirt, who some witness said was seen jumping the 8-foot wooden fence to enter the club.

The tall, heavyset man eventually climbed onstage, as many Alrosa headbangers do.

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“At first we thought it was a hoax, and then when he fired again we knew it was real,” said Jeremy Spencer, 16.

Kozicki, the lighting director, brought up the house lights and ducked under his control table, where he called 911 on his cell phone.

Kozicki peeked from his table to see the gunman holding a man in a headlock. Police said the gunman appeared ready to shoot the hostage, who managed to duck just enough for Officer James D. Niggemeyer to take aim and kill Gale with his shotgun.

All day Thursday, fans left flowers and containers of beer by a boulder at the parking lot entrance, including a six-pack of Heineken with a marijuana bud tucked into the cardboard case.