Officers executed six search warrants while making the eight arrests in four homicides and two attempted murders that occurred between September 2008 and October 2012.
Two homicide victims were targeted, while two other homicides and the attempted murders were random acts of violence, Staff Insp. Greg McLane told a news conference.
"Some of these acts are, as I said, random acts of violence — they've just come upon these people, engaged them, and murdered them," McLane said.
The incidents included a "random" killing in which a man was gunned down in a schoolyard, a "targeted" mid-afternoon fatal shooting on a footpath, and a "random" slaying in which a man was shot in the head while walking his dog.
But McLane stopped short of calling the accused a street gang.
"We can clearly put them with each other," McLane said. "They are a group, and they do hang out, and they do commit criminal offences together."
"I can't really tell you that they're a member of any organized street gang," he added.
Police said some of the accused in the investigation dubbed Project Sugar Horse were already in custody on other matters when they were charged.
McLane said that the investigation is not complete and that detectives were still working on the case.
Investigators are trying to "mine out information that could suggest or help us understand what other acts that they've been responsible for," he said, describing the arrests as a "mere phase in this investigation."
The accused range in age from 19 to 29 and the charges include attempted murder and first-degree murder.
Also on HuffPost