The suspect in the shooting of six people in Maryland and Delaware, including three who died, is in custody.

The Harford County Sheriff's Office in Maryland tweeted Wednesday night that 37-year-old Radee Labeeb Prince was "apprehended a short time ago in Delaware by ATF and allied law enforcement agencies."

Police say Prince shot five co-workers early Wednesday in Edgewood, Maryland, then drove to Wilmington, Delaware, and shot a man he knew at an auto sales and service business. Three of Prince's co-workers at Advanced Granite Solutions died, and two are in critical condition.

The victims have been identified as Bayarsaikhan Tudev, 53, Jose Hidalgo Romero, 34, and Enis Mrvoljak, 48. Officials say two other victims were transported to a hospital where they are in critical condition.

Police said Prince's vehicle was located unoccupied in Delaware around 7 p.m.

His vehicle was believed to be a black GMC Acadia with Delaware plates.

The suspect and the victims were all associated with Advanced Granite Solutions at the Emmorton Business Park in Edgewood.

The gunman was also linked to a later shooting at a used car dealership in Delaware about 55 miles in Wilmington, police said.

Gahler said the suspect used a handgun in the shooting and that it does appear to be a targeted attack. The sheriff's office believe Prince was associated with the business, but could not confirm whether or not he's an employee.

Kevin Doyle of Thornhill Properties said he was getting tools from his truck when he heard screaming and saw three men running from the office park. The men told him someone was shooting and he asked if they had called 911. They said no, even though, Doyle said, they had phones in their hands.

"I think they were just so scared, they didn't (call 911). They had a look of terror," he said.

The Bureau of Alcohol, Tobacco, Firearms and Explosives confirms that special agents from the Baltimore Field Division are on the scene.

Nearby schools have been locked down as a precaution: Edgewood High School, Edgewood Middle School, Deerfield Elementary School, Edgewood Elementary School and William Paca/Old Post Road Elementary School.

The victims and the suspect worked for Advanced Granite Solutions, the owner of the company that designs and installs countertops told The Associated Press. Prince has been an employee for four months, working as a machine operator, owner Barak Caba told AP in a brief telephone interview. Caba was shaken and would not provide additional details.

The wounded were in critical condition with gunshot wounds to the head, according to Maryland Gov. Larry Hogan, who spoke at an unrelated event.

"The killer remains on the loose," Hogan said.

Prince was fired from another job earlier this year after he attacked a co-worker, according to The Baltimore Sun. A former co-worker sought a restraining order against Prince in February, saying he had punched another employee and threatened employees.

"I felt very threatened because he is a big guy and very aggressive on me," the co-worker said in the application for the restraining order. The man said Prince did not get physical with him, but wrote: "I do not want to wait until he will."

A Harford County District Court judge denied the order. The newspaper article did not identify the business or co-worker.

The FBI is assisting local authorities. Investigators were treating the shooting as a case of workplace violence and didn't see ties to terrorism, said Dave Fitz, a spokesman for the Baltimore FBI field office.

There was heavy police presence along Interstate 95 in Maryland and Delaware. Cruisers were stationed in medians, and overhead highway signs displayed a description of Prince's sport utility vehicle and its Delaware license plate.

According to online court records, Prince lived in Elkton — about 35 miles (56 kilometers) from the shooting scene — as recently as last month. He faced several gun charges in March 2015 in Cecil County, including being a felon in possession of a firearm and carrying a handgun in vehicle. However, the charges were dropped about three months later.

A Maryland property manager said Prince often paid his rent late, but was always polite and cooperative. Heather Todd said Prince has rented a three-bedroom town house since November 2014 and lives there with his girlfriend. Her company, Homes for Rent, has filed eight petitions for nonpayment of rent against the couple. But she said they always ended up paying their rent and the company never had to schedule an eviction.

The sheriff said authorities checked an Elkton home after the shooting, but Prince was not there.

Wilmington, Delaware, police said he had relatives in the area there. Police spokeswoman Stephanie Castellani said the victim at the used car lot is best described as an "associate." She said the shooting "was not a random act."