Within hours of friends and family lighting candles at the site of a slain Baton Rouge man, police made an arrest in the slaying of the 21-year-old.

Hardy Allen, 21, 3815 Eaton St., was arrested Wednesday night and booked on counts of first-degree murder, armed robbery and illegal use of a weapon, said Cpl. L’Jean McKneely, a police spokesman.

Earlier in the evening, nearly 100 people released balloons and placed candles on Madison Avenue just feet from where Calvin Chrisentary was shot, as family members recounted how an upstanding man who was always kind to those around him was shot to death near a telephone pole where Madison intersects North Foster Drive.

“He wasn’t the one who would be out and about,” said Chrisentary’s good friend Eric Wallace, who recounted bowling and skating rink trips with him over the years. “He was a humble person.”

Chrisentary was shot in the back shortly before 8:45 p.m. Monday, police have said. Chrisentary was still alive when a neighbor saw him lying in the street and called 911, and his condition was not considered serious when he was taken to a local hospital. He later died of his injuries.

Keon Preston, a teen chaplain with the nonprofit group Stop the Violence, said the family has since learned that Chrisentary was walking to a convenience store less than a block away when Allen approached him from behind and tried to rob him. A struggle ensued and Allen shot Chrisentary, then fled the scene, Preston said.

“It’s senseless for him to be (killed) walking down the street,” said Chrisentary’s mother, Harmika Chrisentary-Payne. “He never hurt anybody. He was always a good kid.”

She added, “It really hurts me. I just feel empty.”

An acquaintance of Allen’s, who declined to be identified out of safety concerns, said Allen recounted the events the day after the shooting. That acquaintance said he reported Allen to police.

For Preston, this shooting death hit especially close to home. Chrisentary was Preston’s cousin, and Preston’s family has already been hit hard by gun violence. Preston’s brother, sister and uncle all have been shot before, but Chrisentary is the first in his family to be killed.

“This has torn me up,” Preston said, adding that he already tries to head out to the scene of every homicide he can to offer support and to counsel neighbors to come together.

“After this, I’m really going to do all I can now,” he said. “I’m going to be out here every day.”

After balloons were released, Preston shared stern words with those gathered about the consequences of gun violence.

“How many people have lost their life due to stupid stuff like this?” he said, urging neighbors to report what they see to local police and equating inaction to letting the violence run unchecked.

“Your friends are dying. People are dropping. This ain’t no joke.”

Alean Johnson, whose 19-year-old son, Demarcus Thomas Sr., was killed in January 2013, briefly shared the story of her loss and how it pains her to see another young man killed.

“You have to be strong to get over this,” she told the mourners. “You don’t get over your child like the common cold.”

She added that police have yet to solve her son’s slaying.

“Thank God you got justice, because I’m still waiting,” she said.

Wanda Mack, who was watching Preston speak from the edge of the crowd, said Chrisentary’s loss was almost too much to bear after the death of her grandson and Preston’s relative Enrico Green, who was gunned down at the age of 15 in 2013.

Mack said she was in near disbelief because she had seen Chrisentary just last week, when he was at her house cleaning her yard and taking care of her place.

With the loss of Chrisentary and Green, Mack said, “I’ve got two burdens to hold.”

But Chrisentary-Payne, Chrisentary’s mother, said she was at least heartened to see so many residents honoring the memory of her son, who leaves behind two young children.

“I didn’t know he touched so many people,” she said.

Follow Daniel Bethencourt on Twitter, @_dbethencourt.