During her decade in office, Ald. Michelle Harris (8th) has talked many times with her City Council colleagues about the gun violence that has battered parts of the South and West sides.

But she says the middle-class neighborhoods in the heart of her ward have largely been spared.

That changed on Christmas night, when two men were killed and five people were wounded after a gunman opened fire on a group of people on the porch of an East Chatham bungalow. The motive isn’t clear. Police are still investigating.

“I’m stunned,” Harris said Monday. “I really am. This is something I’ve never had to deal with.”

The 8600 block of South Maryland Avenue, where the shooting occurred, is in an area of bungalows and other single-family homes that the alderman and other residents describe as “quiet.” Many residents moved there with their families decades ago.

Until the shooting, no gun-related crimes had been reported on the block for more than four years, records show.

“This is not typical for Chatham or Avalon Park,” Harris said. “Chatham is a place I dreamed of living when I was growing up. Everyone wanted to live there. It’s still a beautiful community. . . . This is just off the chain. I’m deeply saddened. I don’t have the words for it.”

Harris said she and other aldermen are searching for answers to the bloodshed that keeps hitting Chicago. “I think we all have these very broad dialogs about what we can do and how we can reach people. But we don’t really know the why, so it’s really difficult to work through it.

“For the residents who live here, it really shakes you to your core. I really wish I had the answers.”

The mass shooting in Chatham was among dozens of violent incidents that left 11 dead and 49 wounded over the long holiday weekend.

Over the Christmas weekend a year ago, six people were slain while 24 others were shot and wounded.

A total of 770 people have been murdered in Chicago so far in 2016, the most in 20 years.

Chicago Police Department officials blamed the violence on gang conflicts and weak gun laws, as they have for years.

“Detectives are making progress in several incidents,” department spokesman Anthony Guglielmi said in a written statement. “We now know that the majority of these shootings and homicides were targeted attacks by gangs against potential rivals who were at holiday gatherings. This was followed by several acts of retaliatory gun violence.”

Police seized 45 illegal guns between Friday and Monday, he added.

The Chatham shooting happened about 9:20 p.m. on Christmas night, when someone wearing a gray hooded sweatshirt walked out from an adjacent alley and opened fire on the group on the porch, according to Chicago Police.

The shooter then ran away from the scene, which is about 100 yards from a bank on 87th Street and about a block from a strip mall anchored by a Walgreens and a Target store.

James Gill, 18, was shot in the head and pronounced dead at the scene, according to police and the Cook County medical examiner’s office. Roy Gill III, 21, was shot multiple times and taken to Christ Medical Center in Oak Lawn, where he was pronounced dead, authorities said.

A 35-year-old man suffered multiple gunshot wounds and was also taken to Christ, where he was listed in critical condition, police said.

A fourth male, whose age was not known, was shot in the body and taken in critical condition to Stroger Hospital, police said. Also, a 27-year-old man and 21-year-old woman both suffered a gunshot wound to the leg and were taken to Stroger, where their conditions were stabilized.

A 39-year-old man shot in the foot later showed up at Roseland Community Hospital, where he was listed in good condition, police said.

“We heard the shots and hit the deck,” a neighbor who asked not to be named said Monday morning. “There’s people in and out of that house all the time.”

Litter, including an empty bottle of Ketel One vodka and empty beer cans, were strewn  across the lawn near police tape that cordoned off the crime scene.

A police officer guarding the scene said at least five shell casings were recovered as the snow covering a patch of grass outside the home melted overnight.

There are several surveillance cameras adjacent to the home and at least two security cameras in buildings 50 yards away.