It appears he may have slipped through the cracks of the criminal justice system, and presumably the companies that hired him either didn't do a thorough background check or decided to give him a chance despite his past. Since the shooting, at least two local officials have questioned whether he should have been out on the street.
WHAT HAS PRINCE BEEN ARRESTED FOR? Prince had more than 42 arrests in Delaware, and several more in Maryland and Washington. In 2003, he pleaded guilty to 15 counts of burglary in Delaware, and was sentenced to 25 years. However, 23 years were suspended, and he served only two years behind bars.
In March 2015, Prince was pulled over in Cecil County, Maryland, for a broken headlight. He was aggressive and screamed at an officer, who found a pistol in Prince's car, according to court documents. He was charged with gun violations, but those charges were dropped.
Interim State's Attorney Steven Trostle said in a statement that prosecutors concluded "that there would be insufficient evidence to convict Mr. Prince." He didn't offer any additional comment. MORE CHARGES DROPPED
Prince faced multiple assault charges between 2001 and 2003 in Delaware, but they were dropped or dismissed. He was charged with offensive touching in 2014 after putting a co-worker in a chokehold, but that case was dismissed.
Last year, Prince was arrested for allegedly assaulting the same man he is accused of shooting in the head at a used car lot in Wilmington, Delaware, on Wednesday after the Maryland shooting. Those charges were dropped.
Carl Kanefsky, a spokesman for the Delaware attorney general's office, said the case was scheduled for trial earlier this year "but the state was unable to go forward based upon available evidence and the absence of a material witness."
Prince faces charges including murder and attempted murder. He has pleaded not guilty. SHOULD PRINCE HAVE BEEN LOCKED UP? In Maryland, Harford County Executive Barry Glassman said that after seeing Prince's criminal record, he was shocked that the man wasn't behind bars.
"The judiciary is going to have to answer for some of the decisions," Glassman said in an interview with WBAL-AM radio. "I think there's some serious inquiries that will have to be looked at regarding that criminal record. ... It raises questions of whether it's preventable or not."
Wilmington Police Chief Bob Tracy said after the suspect's arrest, "if there are violent people who are causing carnage in the community, we've got to find a way to keep them behind bars so they can't go out and re-offend."
HOW DID HE GET A GUN? Because of Prince's criminal record, he hadn't been legally permitted to own a gun since his robbery conviction in 2003. It's not clear how he got a .380 caliber pistol that authorities believe were used in the shootings.
Bureau of Alcohol, Tobacco, Firearms and Explosives spokeswoman Amanda Hils said the agency initiated a trace on the gun but wouldn't release any information about the results. WHAT WAS HIS PAST EMPLOYMENT LIKE?
Prince had a history of intimidating co-workers and employers, and had been recently let go from a different granite company. Just eight months ago, Prince threatened a former employer after he was fired for punching a co-worker. The owner of JPS Marble and Granite, Philip Siason, said in a request for a restraining order that Prince "came to see me, cursed and yelled ... I felt very threatened because he's a big guy and very aggressive on me." Siason also wrote the he knew Prince had illegal guns.
A Harford County judge denied Siason's request for a restraining order, saying only that it did not meet the burden of proof. A message left for the Harford County judge was not returned Friday. A survivor of the rampage at Advanced Granite Solutions said several employees had complained about Prince's behavior to their supervisors.
"Everyone was worried," said the man, who spoke to The Associated Press on the condition of anonymity because he was afraid of retaliation, and has concerns about his family's immigration status. Ron Cherry, an attorney for the company, said he couldn't respond to questions about Prince.