During the press conference, Commissioner Bill Evans mentioned the gun was an "automatic Glock 40mm" and then a "high-velocity 40 mm Glock handgun."
In response to the shooting, a police spokesman, Evans , and Mayor Marty Walsh have all stated "there are too many guns on the street."
"Armed career criminal" appears to be a term for criminals who skate on gun-related charges to reoffend.
http://www.boston.com/news/local/massac ... t_Reads_hp
“In our minds, he’s a hero,” Evans said he told the officer, “because he’s out there doing God’s work, and that’s taking guns off the street.”
If the article is to be believed, the suspect previously had pleaded guilty to possession of a firearm without a license in 2012, carrying a gun without a license in 2006, a second gun-related charge from that same arrest, and a previous arrest for either possession of or carrying a gun without a license. (It's unclear which based on the articles I read.)“Thank God the suspect also wasn’t shot in the situation,” Evans said.
ETA: The suspect was also arraigned in 2010 for possession of a firearm with a defaced serial number.