CARSON CITY, Nev.  — The burst of bullets came suddenly in Nevada’s capital.

Just before 9 a.m., the gunman stepped onto an IHOP parking lot from his blue minivan with a yellow “Support Our Troops” sticker on it. He opened fire, then continued into the restaurant and marched resolutely toward a table of uniformed National Guard members before shooting each one of them, and fatally wounding three of them, authorities said.

Eduardo Sencion would kill four people and wound seven others in all before shooting himself in the head in front of a bustling business complex in an unexplained display of violence Tuesday. One of the wounded, a woman and National Guard member, would later die at an area hospital.

The breakfast-time massacre sent tremors of fear through Carson City at a time when lawmakers were not in session. In the immediate confusion after the shooting, officials prepared for a citywide assault.

A motive remained unknown late Tuesday, as lawmakers, business owners and law enforcement officials in this close-knit, government-driven city of 50,000 struggled to understand what drove Sencion to turn an AK-47 assault rifle on his hometown.

Authorities are investigating whether the military members were targeted. Carson City Sheriff Kenny Furlong told The Associated Press on Tuesday night that authorities, at that point, did not think the shooter set out to target people in military.

“But of course, it’s clearly a heavy, heavy concern from here,” he added.

Sencion shot each of the five Nevada National Guard troops sitting together at the back of the restaurant. Another woman was shot and killed.

Family members told investigators that Sencion, 32, was mentally troubled, but he did not have a criminal history. He was pronounced dead at a local hospital hours after the mass shooting.

“The sheriff may never know the motive,” Nevada Highway Patrol spokesman Chuck Allen said.

The shooting started just before 9 a.m. roughly two miles from the state Capitol in Carson City.

Sencion stepped out of the minivan and immediately shot a woman near a motorcycle before charging into the chain restaurant. Witnesses said he had unloaded a magazine when he was still less than 12 feet from his car.

The gunfire prompted Ralph Swagler, the owner of a nearby barbecue restaurant, to grab his weapon. But when Sencion started toward him, Swagler backed away.

“I wish I had shot at him when he was going in the IHOP,” said Swagler, who owns Locals BBQ & Grill. “But when he came at me, when somebody is pointing an automatic weapon at you — you can’t believe the firepower, the kind of rounds coming out of that weapon.”

Sencion struck each of the Guard members in the restaurant in what witnesses described as a seemingly intentional attack. He then exited the restaurant and fired shots toward the barbecue restaurant, shattering the windows. He also fired toward an H&R Block and a casino across the street.

Sencion had shot himself and was lying injured in the parking lot by the time officers arrived. A crowd of reporters and onlookers could see a body on the ground, covered with a white sheet except for the feet, clad in tan boots.

Fran Hunter is a frequent IHOP customer who works in a pet supply store next door but made a last second decision Tuesday to eat at the casino coffee shop across the street.

“It turned out to be a good decision,” she told the AP. “If you know the IHOP, they had to be sitting ducks with that long narrow aisle — if they were at those tables with no way to get out.”

Servicemen flocked to a Reno hospital after the shooting, nervously waiting for word on those killed and hurt.

“It’s hard to believe something like this would happen to really good people,” said Spc. Lee Amato, 33, a Nevada Army National Guard member. “It’s like a hole, something taken away. It’s mind-boggling and hard to comprehend.”

Sgt. 1st class Cameron Anderson, 31, of Reno, was tasked with driving the Guard’s chaplain to the hospital

“You go a whole tour in Afghanistan and no one is shot,” Anderson said. “And you go to IHOP and several are shot. It’s a shock.”

The names of the victims, including the three Guard members — a woman and two men — who were killed, were not immediately released.