Correction: An earlier version of this story misstated the number of homicides that have taken place on or near parkland or a recreation center covered by Maryland-National Capital Park Police in Prince George's since May 2014. This version has been updated.

J.R. Reid Franklin was an emerging rapper whose fiery verses caught the ears of thousands online. He was supposed to take the stage Monday night at a D.C. club under his stage name, “Rollin Reid.”

Instead, family, friends and fans were mourning the 22-year-old Prince George’s man who was shot and killed at the crowded Bradbury Heights Recreation Center in Suitland on Sunday.

Franklin was a beloved son, a dedicated father to 4-year-old Jaylen, and an artist with big dreams, his family said a day after his death in the neighborhood where he grew up.

“He was my baby, and he was only 22,” his mother, Fern Franklin, 59, said. “He was trying to get his stuff together, and he was working.”

Franklin, who lived in Temple Hills, was found in the parking lot of the recreation center about 5:30 p.m, in what authorities called a “brazen, bold” attack. Prince George’s County Police and Maryland-National Capital Park Police are investigating the slaying; officials have not named any suspects.

Police said the shooting started after an argument between Franklin and others in the parking lot of the recreation center. It is unclear what the argument was about. Police said a group ran from the scene after the shooting.

Franklin’s mother said he might have been meeting friends to play basketball when the attack occurred.

“He grew up down there,” she said.

Franklin’s sister, 38-year-old Catrina Brown of Bowie, said it’s possible that her brother had planned to meet some friends at the recreation center after his shift at P.F. Chang’s, where she said he worked as a waiter.

“He was working, trying to take care of his son, and he had a true love for music,” Brown said. “He was really heavily into music.”

Brown touted Jay Z as one of his influences. His mother said Franklin enjoyed throwing the football with his son and taking him out on his kid-size dirt bike. During football season, father and son watched the Dallas Cowboys — Jaylen’s favorite team.

Fern Franklin said she had no idea of a possible motive for the attack. She said young people need to “get off their phones and stuff and do something positive, something better.”

The day of the killing, a song was promoted on Franklin’s Instagram account titled “Dead Man Walkin.” It appeared to be aimed at another area rapper, and the artwork features a sign of a recreation center on Ewing Avenue where Bradbury Heights is located.

Authorities would not comment specifically on Franklin’s social media accounts, citing the ongoing investigation, but Park Police Executive Lt. Brian Waters said detectives are looking at every angle.

“We live in an age where social media is relevant to everything,” Waters said.

Friends on Twitter expressed grief and dismay at Franklin’s slaying.

“He Was Just Talking About His Mixtape Releasing,” @CalasoLivinSuav, tweeted, using the hashtag #RIPReid. @ZonedOut_Dnice tweeted, “All he was trying do is come up,” adding icons for a dollar sign and money with wings.

Some decried the violence that has recently shaken parts of Prince George’s.

This weekend’s shooting was the sixth homicide that has taken place on or near parkland or a recreation center covered by Maryland-National Capital Park Police in the county since May 2014, Waters said.

The six homicides — a result of eight shootings and two stabbings reported on and near park property in the county in slightly more than a year — is extraordinarily high, Waters said.

“Regionwide, there is this phenomenon of ultraviolence,” Waters said. “A lot of jurisdictions are bearing the brunt of this surge in violence, and we are part of that.”

D.C. Police Chief Cathy L. Lanier recently convened her counterparts from large cities across the country to discuss the increase in the shootings and violent crime in their communities. The 35 cities that participated in a survey by the Major Cities Chiefs Association reported an average increase in homicides of about 20 percent.

Waters said Maryland­National Capital Park Police have been working closely with Prince George’s police and other agencies to get a handle on the violence on parkland.

“That has raised an alarm in terms of being as smart as we can be to respond to it,” he said.

Family gathered at the home of Franklin’s mother Monday to make funeral arrangements. Fern Franklin said that Jaylen is getting ready to start pre­kindergarten. The account used to promote Franklin’s music also featured images of his son.

The news that Franklin would not be coming home, the family said, left them in a state of shock.

“She’s trying to grasp all of it,” Catrina Brown said of her mother. “He was her baby son. He was loved by many. It’s a huge loss to our family.”

A vigil in Franklin’s honor is planned for Wednesday night at the location of the shooting.