A 20 year-old woman was killed and three others wounded by two hooded gunman Sunday night in a brazen ambush on a leafy and normally peaceful Mattapan sidestreet. The incident has ratcheted up fears of escalating gang activity in a residential section off River Street more known for its well-kept yards and tide single-family homes than for the crackle of gunfire.

The murder of Tia Francis - who police insist was not the target of the 9:55 p.m. attack - happened at the corner of Gladeside Avenue and Gladeside Terrace. Three men - including a 17 year-old Mattapan resident - were treated and later released for non-threatening gunshot wounds. Boston Police insisted this week that Francis was not the intended target of the attack, but implied that one of the wounded men may have been.

"We have intelligence that suggests there are feuding gangs in the area that have been exchanging fire," said Boston Police spokesperson Elaine Driscoll. She said investigators know more information about the gangs involved, but refused to provide further details. Police have not made any arrests in the shooting as of Wednesday, a fact that left several nearby residents fearful of speaking publicly to reporters.

The incident came as Boston Police prepared to roll out an aggressive new "street team" deployment that will canvass several new sections of the city with daily walking patrols. The initiative, announced Tuesday afternoon in Codman Square, will re-deploy officers from their typical tours of duty into five-person teams that will saturate the chosen areas on foot. Locally, that will include two teams on either side of Codman Square, Morton Street and Blue Hill Ave., and the Blue Hill-Talbot -Franklin Field area.

During his remarks announcing the deployment, Commissioner Ed Davis spoke pointedly about Francis's murder and another recent shooting on Columbia Road that injured a young mother walking with a toddler.

"These were innocent women who were going about their business in this city," Davis said. "I often hear people talk about crime in terms of warfare and soldiers. This is not a war. These people are not soldiers. These are neighbors killing neighbors. And we need to step up and say to these people that it must stop."

Earlier in the day, neighbors tending to their lawn on Gladeside Avenue said they doubted that the perpetrators of the Sunday ambush were from the immediate neighborhood.

"I've never seen nothing like that around here, never even just regular fighting," said one homeowner, who said he's lived on Gladeside since 1982. Speeding mopeds, he said, were his biggest concern until Sunday night.

However, another local resident - who also requested anonymity - said that the corner of Gladeside Terrace was a bubbling problem prior to the shooting, with groups of teens and older adults hanging out at late hours. The same resident said that sounds of gunfire have been heard recently at nearby Ryan Playground, a much-used city park across River Street.

"It sounds like they use it for practice. Neighbors don't even call about it anymore," said the resident, who said he hopes to reinvigorate a defunct crime watch group that once met in the warren of sidestreets in the Gladeside area.

"I think there's been a lapse in the enforcement," the resident said. "We need a more aggressive approach to dealing with people who don't live here just hanging out."

Captain James Claiborne, the police commander at Area B-3 which covers the scene of the shooting, said that he was not even familiar with the name Gladeside Avenue before Sunday's shooting. A Reporter review of recent police log entries shows only one entry since the start of the summer: a July 17 arrest of a Ridgewood Street man on cocaine trafficking charges was listed at "0 Gladeside Ave."

Still, violence has come close to home in recent months: A 17 year-old Lorna Road boy, Mariotis Harris, was found shot to death in the woods of the Gladeside Urban Wild on June 3. The entrance to the city-owned urban wild, which includes nature trails for walkers but is little used, according to neighbors is located just steps from the scene of Sunday's shooting. The Harris murder case remains unsolved and under investigation, according to Boston Police.

This week, a neighbor on Gladeside Ave., whose home abuts the urban wild, said he did not even know about the discovery of the dead teen, and knew little about Tia Francis, a college student who grew up in a home just steps from where she was gunned down.

"People here don't really know each other that well," the neighbor admitted.

A flyer adorned with the young woman's photo, posted on the door of the Francis family home this week, respectfully asked media to allow them to "grieve in private."

"Know that Tia was a beautiful person, inside and out," the flyer read.