Demitrius Moore, 15, finished his chores before walking out the door of his North Philadelphia home on Saturday afternoon, washing three loads of laundry for his mother and younger brothers before leaving to visit his father’s house.

Moore never made it. On the way, he was shot twice in the chest by a gunman who remained at large Monday, leaving Moore’s relatives wondering why he was gunned down and planning funeral arrangements for the teen they called “Man-man."

“They shot my baby right in his heart,” Moore’s mother, Rasheida Quinn, said Monday, crying as a friend embraced her.

Philadelphia police released few details about Moore’s killing, which was part of a barrage of violence in the city over the weekend. In less than 48 hours, police said, seven people were killed and 12 others were wounded by gunfire, including a 44-year-old man shot in a hand and leg when he was robbed of $4, and an 18-month-old boy who suffered a graze wound to the head.

The violence spanned neighborhoods across the city and was particularly acute Sunday, when 10 people were killed or injured in less than 10 hours, police said.

The outburst pushed the city’s homicide total to 14 in the first 12 days of the year, police statistics show, the most killings this early in a year in five years.

Gun violence has continued to plague the city even as other violent crime tallies remain relatively low: 356 people were slain last year, the highest total since 2007, and more than 1,400 people were shot, the highest total since 2010.

Mayor Jim Kenney on Monday expressed frustration over what he called an “overwhelming weekend,” and over how many people can access guns, whether legally purchased or bought on the street.

“The guns are still the one part of this that we can’t control,” Kenney said after an unrelated news conference in Rhawnhurst, referring to the city’s inability under state law to enact its own gun regulations.

Police said the weekend’s incidents remained under investigation, and most had not yet resulted in arrests.

In Moore’s case, his mother said she learned what happened when detectives knocked on her door Saturday. Police said the 15-year-old was fatally shot on the 3100 block of North Rosewood Street around 1:35 p.m. and pronounced dead about 15 minutes later at Temple University Hospital.

Quinn said her son had regularly helped out around the house and looked after his five younger brothers, and was a typical teenager who liked rap music, girls, basketball, and clothes.

Quinn said that her son got in trouble recently after he was caught joyriding in a stolen car, but that he’d stayed out of trouble since. She said she hoped surveillance footage would help police find his killer.

Her family has regularly heard gunshots near their home on the 2600 block of North 12th Street, Quinn said. The neighborhood once had a few people who went by the nickname “Man-man,” but over the years, bursts of violence had claimed all but her son.

“Once he said to me, ‘Mom, I’m the last of the Man-mans,’ ” Quinn said.

The other victims killed during the weekend were all men between the ages of 23 and 35, according to police.

On Saturday night, a 35-year-old man whom police did not identify was fatally stabbed in the neck on the 100 block of South 17th Street. Police said someone had been taken into custody, but they did not provide further details Monday.

A witness told The Inquirer this weekend that he was sitting in his car when he saw a fight among three men spill out from between parked cars; one of the men then pulled out a large knife.

An 18-month-old toddler was shot in East Germantown on Sunday on the 100 block of East Pastorius Street during an incident in which a 26-year-old man was also struck in a shoulder. Both were hospitalized in stable condition, police said.

Acting Police Commissioner Christine M. Coulter told reporters at the scene that there was “no doubt” the gunman knew they were firing with a child in range: “They had to see the kid. They were right up" on the victims.

Amid the spree of crimes, Kenney said, city officials would do “everything we can” to reduce the violence, adding that as police continue to investigate, community crisis responders were being sent to affected neighborhoods and seeking to speak to residents and help prevent retaliation.

Still, the violence continued Monday, with two homicides reported among several shootings.

Police said a 19-year-old man was killed around 11 a.m. on the 1900 block of Georgian Road in West Oak Lane when he was shot several times in the head.

The city recorded the second slaying just before 5:30 p.m., when a 26-year-old man was shot in the neck while in the 2600 block of West Cumberland Street. Medics pronounced him dead at the scene.

Police reported no arrests in either killing.

Two men, ages 33 and 24, were shot on the 900 block of North 11th Street around 2:56 p.m. Authorities said that each was taken to Temple University Hospital and that their conditions were not known.

At 3:13 p.m., a 28-year-old man was shot four times on the 5100 block of Catharine Street. He was taken to Penn Presbyterian Medical Center in stable condition, police said.

And less than an hour later, around 4:10 p.m., a 20-year-old man was shot once in a thigh on the 4400 block of Holden Street in West Philadelphia. He was hospitalized in stable condition, police said.

Staff writers Patricia Madej and Robert Moran contributed to this article.