Police arrested Radee Labeeb Prince, 37, Wednesday evening, hours after he allegedly opened fire at his workplace in Edgewood, Maryland.
In addition to the three people killed in the shooting rampage in Maryland, an additional two others were wounded, authorities said.
But that was just the first incident in a deadly mayhem that started in Maryland and ended with another shooting about 40 miles away in Delaware.
In the 10 hours that Prince was on the run, he drove across state lines, shot a sixth person at a Delaware car dealership and led police on car and foot chases, officials said.
8:58 a.m.: Shooting rampage in Maryland
The series of shootings started shortly before 9 a.m.
Prince was working as a machine operator for Advanced Granite Solutions, a home remodeling business in Edgewood. The city is roughly 30 miles northeast of Baltimore.
He started working there about four months ago and was scheduled to work Wednesday, according to Harford County Sheriff Jeffrey Gahler.
But what could have been a regular work day turned deadly.
At 8:58 a.m., police were called to the business. When they arrived about four minutes later, they found several employees shot.
Three victims Bayarsaikhan Tudev, 53, of Virginia; Jose Hidalgo Romero, 34 of Aberdeen, Maryland; and Enis Mrvoljak, 48, of Dundalk, Maryland were killed.
Two others were injured and remained hospitalized in critical condition Wednesday night, officials said.
Prince shot the five victims with a handgun and acted alone, officials said. It was unclear why he did it.
"Unfortunately, like most suburban counties in America, we are not immune to workplace violence," Harford County Executive Barry Glassman said after the shooting.
10:46 a.m.: A second shooting
Prince fled after the shooting, prompting a massive manhunt.
He drove about 55 miles away to a car dealership in Wilmington, Delaware. At 10:46 a.m., he opened fire on a man who knew him.
The victim was shot several times and took a gunshot to the head, police said.
Despite his injuries, the man was conscious when officers arrived and he gave them Prince's name and a description of his vehicle, Wilmington Police Chief Robert Tracy said.
Police, who had received an earlier alert about Prince from Maryland officials, spotted the vehicle leaving the scene and briefly chased it, before losing it.
"This individual knew the people he wanted to go shoot," Tracy said earlier of the six victims. "This wasn't a random act of violence where the person went out indiscriminately and was shooting people up."
The police chief said Prince and the Wilmington victim have "had beefs, and they've had history together," but did not elaborate.
Prince has a lengthy criminal history, including 42 arrests, mostly for probation violations, and 15 felony convictions, Tracy said.
5:35 p.m.: A key tip
The search for the suspect quickly intensified.
Prince's photo was put up on FBI billboards along Interstate 95 from Philadelphia to Washington, D.C. and over Atlantic City, CNN affiliate WBAL reported.
Schools in both Maryland and Delaware were locked down and photos of him and of his vehicle -- a 2008 black GMC Acadia SUV -- emerged on social media.
"There's an individual out there on the loose who committed one of the most heinous acts we've ever seen in our county. Certainly, we consider him armed and dangerous," Harford County Sheriff Jeffrey Gahler said.
Local, state and federal agencies searched for Prince's SUV unsuccessfully for hours.
"We were everywhere. There was no stone that wasn't unturned in what we had covered," Tracy said.
Then at 5:35 p.m., a tip came, according to Tracy.
Prince had traveled about 15 miles from the scene of the second shooting and a bystander spotted him.
The tipster saw Prince leave the SUV and walk toward Glasgow High School in Newark, Delaware, according to Tracy.
7:05 p.m.: The arrest
Authorities set up a perimeter and desperately tried to find him.
Three agents with the Bureau of Alcohol, Tobacco, Firearms and Explosives who were among other authorities searching for the suspect spotted Prince walking near the school and smoking a cigar, a law enforcement official involved in the investigation told CNN.
Agents briefly chased Prince before they arrested him at 7:05 p.m., Tracy said.
During the chase, he tossed a .380-caliber gun that matched the caliber of the shells at the Maryland crime scene, the law enforcement source said.
"This brings somewhat closure and conclusion to a brief manhunt," Tracy said.
Prince never made it onto the high school grounds.