A group of Chicago mothers who have been patrolling a two-block stretch of South Stewart Avenue in the city’s Englewood neighborhood are celebrating three summers without a fatal shooting.

“We’re doing better than most neighborhoods in Chicago and we’re definitely doing better than most areas in Englewood,” Tamar Manasseh, a mother of two who grew up in the area, told local television news.

Manasseh, 38, founded Mothers Against Senseless Killings (MASK) out of a sense of frustration with persistent gun violence in her neighborhood. The last straw came in June 2015, when three women were shot, one fatally, near the corner of 75th Street and South Stewart Avenue.

Three days later, donning hot pink T-shirts that read “Moms on Patrol” and armed with folding chairs, Manasseh and about a dozen women set up shop on the block. They vowed to serve as a deterrent to shootings.

“People are less likely to commit violent acts against people they know,” Manasseh, told Good Housekeeping in an interview. “The idea is to make sure we know our neighbors, so that no one’s a stranger anymore.”

As Maya Dukmasova reported in her profile of MASK for The Trace, the mothers quickly became a neighborhood fixture, patrolling a one-mile radius around 75th Street every day from 4 p.m. to 8 p.m., and holding barbecues and pizza parties in an effort to engage the local children.

Two months after forming, MASK hit a disappointing setback. A man was fatally shot one block away, at 75th and South Harvard Avenue. But in the two summers since then, only three people have been shot within a two-block radius of the group’s corner. All the victims survived. According to MASK, none of the shootings occurred while members were on patrol.

Mothers in other Chicago neighborhoods and in other cities have been inspired to form their own chapters: The program now has branches in Staten Island, New York; Evansville, Indiana; and Memphis, Tennessee.

“MASK is not just an organization, it’s turning into a movement,” Manasseh told Chicago magazine last year.

On September 3, roughly 600 people turned up for MASK’s end-of-summer block party in Englewood, which celebrated the group’s three-summer milestone.

“Any block can be changed,” Manasseh told reporters. “All you have to do is care.”