George Carter, the 15-year-old boy whose passionate support for improving public education in New Orleans made his killing in the Desire neighborhood last month all the more painful, has been identified as a suspect in an armed robbery of a store that took place just a day before his murder and a few blocks from where his body was discovered, according to the store’s owner and a law enforcement source.

A Police Department spokesman declined Friday to provide details of the investigation into either Carter’s slaying or the robbery, which happened at the Louisa Mini Mart, 3423 Louisa St., just after midnight Oct. 20.

NOPD spokesman Tyler Gamble also declined to say whether detectives have implicated Carter in the robbery. Gamble said a 16-year-old whom police did not name was arrested for the robbery, in which two young males were caught on a security camera.

Another law enforcement source confirmed, however, that detectives suspect Carter in the robbery and are investigating a tie between that crime and his killing.

Carter, a longtime member of Kids Rethink New Orleans Schools, a youth organization he joined at age 7, was found shot dead in the middle of the 3500 block of Piety Street shortly after 7 a.m. the day after the robbery. The street runs parallel and a block over from Louisa, near Higgins Boulevard.

Carter’s death brought sorrow to a community of youth advocates who called him a shining, eloquent voice for issues ranging from building school gardens to ending the so-called “school-to-prison pipeline.”

Carter was involved with projects that included designing school facilities, making short films and writing a graphic novel.

Nobody has been arrested in his killing. Gamble said detectives are still investigating a possible connection between the two crimes.

According to a police report, a young, black male entered the store with a red bandana partially covering his face, pointed a gun at the clerk and demanded all the cash from the register.

After the clerk complied, the gunman also demanded a semiautomatic pistol that was kept behind the counter.

A second robber, who the store’s owner said was Carter, wore a red bandana around his neck with a red-and-black hooded jacket.

He had walked into the store earlier, taking a bottle of water from the cooler and bringing it to the counter before the other assailant walked in, the report said.

Another witness told police that the second robber had been in the store a half-hour earlier. Both assailants ran down Louisa Street together.

Police were able to lift partial fingerprints from the water bottle, the police report said, though Gamble said detectives are still investigating those prints.

The store’s owner, who spoke on condition of anonymity, said the culprits took $1,000 and the gun, and that the clerk on duty identified Carter in a police photo lineup.

“He wasn’t wearing a mask. (The store clerk) picked him out of the lineup,” said the owner, who wasn’t present during the robbery.

“The cashier, the police are all saying it was him. He didn’t have any other reason to die for,” the owner said, suggesting a link between the two crimes.

He said the store turned over its surveillance footage to police.

“They came here a couple of times, like they were thinking about it. We’ve seen him in the store before. He’s robbing now, and it’s like he’s a hero,” the owner said. “He didn’t come in with a mask. It was just a matter of time. He probably got killed to not say anything.”

Asked about the supposed photo identification, Gamble said, “I can’t confirm that at this time.”

Carter was enrolled since August at the NET Charter High School. He continued to be active in the youth leadership development group, where he had referred to himself as a “pre-thinker” because of how early he started.

Karen “KG” Marshall, the group’s executive director, said Carter had returned from summer school to become more involved in the organization’s program for high school, after also being involved in the spring.

Marshall said she has heard contradictory rumors about Carter’s involvement in crime but that it would shock her if he were involved in anything violent.

“I’d be really surprised if any of that were true,” she said, citing “the way he interacted, and the things he envisioned and wanted for the city — and my interactions with George.

“He seemed pretty responsible. Smart, too. George was a young person. He was a teenager, and also he had amazing dreams for what he wanted to do. His involvement with Rethink was wonderful. It seems like we have to deify young people to feel OK to mourn their deaths, but overall I’d be incredibly shocked. That’s just not the person I know George to be.”

Tabitha Mustafa, a local social justice organizer and investigator with the Louisiana Center for Children’s Rights, was measured in her reaction to the allegation of Carter’s involvement in a crime.

“It shouldn’t change the public’s view of George Carter. He was still a Rethinker, still a visionary,” she said. “People’s lives are very nuanced, and it seems the general population forgets that when it involves an act of violence. If indeed he was involved, I’m sure that there’s more to the story than he just went into a store and robbed someone.

“There’s also no confirmed proof that he was the youth involved. If he had been in something, it really doesn’t change the way I see him and a lot of people saw him.”

Follow John Simerman on Twitter, @johnsimerman.