Radee Labeeb Prince was also involved in a later shooting about 55 miles away in Wilmington, Delaware, Wilmington police confirmed.
A manhunt was underway for 37-year-old Radee Labeeb Prince, who was associated with the granite business where the shootings took place, said Harford County Sheriff Jeffrey Gahler. The victims and the suspect worked for Advanced Granite Solutions.
"The 37-year-old suspect is considered armed and risky, police said, adding that they are searching for him". Davis urged anyone who sees him not to approach him, but to call 911.
"He came back to our business justifying what he did was right because the other guy was saying some things that he did not like", the employee claimed in the filing, adding that Prince returned to the office three times after he was sacked.
Multiple businesses in the area were reportedly on lockdown.
A manhunt is underway for the 37-year-old Prince, who is considered armed and risky.More news: Match abandoned in Hyderabad as India, Australia share T20 series
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The identities of the victims were not released immediately.
He said authorities in helicopters and on the ground were searching for Prince, who may be driving a black 2008 GMC Acadia with the DE licence plate PC64273.
A former co-worker sought a restraining order against him in February, the paper reports.
The Baltimore Sun reports Prince was sacked from another job earlier this year after he attacked a co-worker.
A fourth time, Prince allegedly "came to see me, cursed and yelled at me..."
"On the advice of the Harford County Sheriff's Office, these schools are now on modified lockdown due to an incident in the surrounding community", the Harford County school district said. However, the charges were dropped three months later, according to The Sun.