The city has its third-highest number of homicides ever - 55 - with a few days to go yet this year, and had an all-time high of 67 slayings last year.
"It doesn't scare me. I grew up in Camden, so I'm used to the urban environment," said Matias, who hit the streets Dec. 19. "It's not anything I'm not used to, and it's a positive way to be involved in my community."
Matias also speaks Spanish, and is one of dozens of the new officers who speak a second language. Seventeen languages are represented on the force, including Polish, Arabic, French, Malayalam, Portuguese, Haitian Creole, and American Sign. More than 50 percent of the new recruits hold a four-year degree or higher.
"Far more valuable than a night stick or a service weapon is a police officer's ability to communicate. It's how we de-escalate violent situations, obtain information on criminals, render aid, and build relationships based upon trust with the community," said County Police Chief Scott Thomson.
Coming off six months of training, Jovon Plaza, 20, can quickly list the 10 deadly errors - a list learned at the academy - as can his partner for the day, Abigail Pillot, 33. They agree it's one of the most important things they learned there.
"Poor attitude, poor search, poor cuffing, relaxing too soon," Plaza said. "It's one of a bunch of mottos or creeds we memorize to understand what we need to do to stay safe."
The graduated cadets come from all over New Jersey and include 11 women. Lissandra Sime, one of several officers on the force who speaks Spanish, patrolled the streets of North Camden on Friday afternoon, chatting with store owners and passersby.
Sime, who moved to Camden 13 years ago from the Dominican Republic, attended Rowan to study accounting and worked with the St. Joseph's Carpenter Society before joining the force.
Growing up in East Camden, Sime and her brother weren't allowed outside - not even on the porch to play.
"My mother thought it was too dangerous. She feared something would happen to us," Sime said.
On Friday, Sime and a group of new recruits reported for roll call, received their neighborhood assignments, and spent eight hours canvassing North Camden. Drivers passing honked in approval.
Freddy Simpson, 65, self-described as the "mayor" of North Camden, saluted the officers.
"You got kids playing in the streets," Simpson said, gesturing toward two girls riding by on bicycles. "I've been trying to keep the streets clean 50 years. They finally arrived."
Along Sixth and Elm Streets, Sime spotted a man ducking into an alley known to be popular with drug dealers and users. She saw the man produce a bag of white powder and a syringe, and approached with her field training officer. The man didn't run, and Sime explained that he was under arrest for possession.
The county force began to patrol the city May 1 after the longtime city department was disbanded in what was called an effort to improve service and save money. Initially, officers were concentrated on the Parkside and Fairview neighborhoods.
Residents and store owners in North Camden, which had not been the focus of the first deployment of officers, say that since the new officers arrived, the drug traffic has slowed considerably.
With four to five officers walking around in groups, it's hard to avoid them, even in North Camden, with its many alleys and abandoned buildings.
"They got the place locked down," said Jason Walls of Lindenwold, who said he has worked at Tony & Ruth's Steaks on Eighth Street in North Camden for four years. "It's nice to walk down the street and not worry about getting shot. No one stands outside anymore. I hope it stays like this, that they keep it up."
The plan, Thomson said, is for officers to continue the canvassing for the next 12 weeks as part of a field training program involving mentoring with veteran officers and an opportunity to get to know the landscape and people. "This type of indoctrination has the residents training our officers almost as much as the veteran cop," Thomson said.
In a city with high rates of violent crime, small drug arrests might not seem so important, but field training officer Rafael Martinez Jr. said drugs fuel violent crime, as dealers ripping off dealers and gang turf wars account for many of the slayings in Camden's streets.
Toward the end of their shift, Sime and the other officers stopped into La Dominicana, the store on North Seventh Street where Matias' uncle was killed.
Espinal's family still owns and runs the store, and his daughter, Milca Madera, happened to stop in with her daughters.
"We're carrying on his tradition and we're glad that it's inspired her to do something to change things and hopefully drive down the killings," she said of Matias.