In a late-night press conference on Thursday, authorities offered few details about how Mohammad Youssef Abdul­azeez, 24, attacked a recruiting center and a Navy and Marine reserve center in Chattanooga, Tenn.

“We are at the beginning of this investigation,” FBI agent Ed Reinhold said. “We still have three active crime scenes. … If you have info please contact us: (865) 602-7582.”

Pieced together from eyewitness accounts and news reports, here is what we know so far.

Abdul­azeez has not been shown to be following promptings of the Islamic State to attack Americans. He was born in Kuwait and became a U.S. citizen; he was Muslim from a conservative, middle-class family; he was an electrical engineer and an amateur MMA fighter; he made pointed jokes about his name causing national security alerts; he was recently arrested for driving under the influence; in the past few days, he blogged about jihad.

“We’re all just shocked. I really still don’t think he did it,” Levon Miller, a former high school wrestling teammate of the suspect, told the Boston Herald. “He was an easygoing kid, he was a good guy.”

But though he may once have been a good guy, authorities said Abdul­azeez drove up to a military recruiting center on Old Lee Highway Road in a rented silver convertible Mustang at around 10:30 a.m. on Thursday. Armed with more than one weapon — the FBI hasn’t said what kind — he started firing.

“He never got out of the car,” Gina Mule told CNN. “He had a big, huge, high-powered rifle, and he was unloading shots right into the recruiters.”

The barrage was terrifying, but unfocused.

“It was obvious that they were intentionally shooting at all five branches of the military,” Keith Wheatley, the property manager of the recruiting center building, told the Chattanooga Times Free Press. The aftermath “looked like a TV set” of a bullet-riddled crime scene, he said.

Dropped off by his dad at 10:30 to sign up for the Air Force, Nicholas Gray huddled in a storage room during the attack, emerging to call his father afterward.

“Hey, I don’t know if you’ve heard, I’m fine,” he told his father — with a bullet reportedly lodged in his backpack

Abdul­azeez got off up to 30 rounds, according to guesses by eyewitnesses, but fortunately, this attack proved largely ineffective. One recruiter was hit, but treated and released.

He then drove to a second target about seven miles away, reportedly in a rental car. Those at Chattanooga’s Navy Operational Support Center — would be less lucky. The center is “used by both Navy and Marine personnel to provide training and readiness support for reserve components to support the services,” as the Times Free Press put it. Abdul­azeez arrived there around 11 a.m. and opened fire.

“I couldn’t even begin to tell you how many,” Marilyn Hutcheson, who works across the street, told the Tennessean when asked about the number of shots. “It was rapid-fire, like ‘pow-pow-pow-pow-pow,’ so quickly. The next thing I knew, there were police cars coming from every direction.”

When police came, a gunfight ensued. Chattanooga and Hamilton County officers “actively and enthusiastically” engaged Abdul­azeez, as Chattanooga Police Chief Fred Fletcher told reporters.

“At least 100, at least, because it was several at one time,” Carolyn Taylor, who works across the street, told the New York Times when asked about the number of shots. “Within seconds, we heard the gunfire.”

Abdul­azeez — armed with an “AK-47 style weapon,” as CNN reported — held out for some time, but reportedly rammed his car into a gate and was killed by police. Before his death, he killed four Marines and injured three others at the support center.

The victims have not all been named, but one appears to be a Chattanooga police officer who was shot in the ankle and is now in stable condition. Another appears to be a Navy sailor reportedly shot multiple times and critically injured.

In the afternoon, law enforcement surrounded and searched Abdulazeez’s home in Hixson, Tenn. It’s not known what was found; two women in the home were handcuffed, but officials later said this was standard procedure when searching a residence.

“We’ve never had any problems like this,” one of Abdulazeez’s neighbors told Nashville’s WKRN-TV. “I’d never suspect anything,”

More details will undoubtedly emerge in a press conference scheduled for 3 p.m. today. But one thing was clear.

“It’s been a long day for our city,” Chattanooga Mayor Andy Berke (D) said Thursday night.