Family members of Earl Andrews and Monquiarious Caldwell attend a prayer vigil in honor of the two friends, who were shot and killed on the Grambing State University campus. (Hannah Baldwin/The News-Star via AP)

First came the calls to Grambling State University’s police chief, Gene Caviness, around midnight Tuesday, with distraught students reporting shots fired on the campus in northern Louisiana.

Then police found Earl Andrews, a 23-year-old Grambling senior, and his friend Monquiarious Caldwell, also 23. They were on the ground in a residential courtyard, both dead from gunshot wounds.

Jaylin M. Wayne. (Lincoln Paris Sheriff’s Department)

On Thursday, police arrested Jaylin M. Wayne, of St. Louis, after he turned himself in to law enforcement. He has been charged with first-degree murder.

Wayne is a freshman at the historically black university, school officials said.

The Lincoln Parish Sheriff’s Department said the incident began with a disagreement between Wayne and Andrews. At some point during the fight, Wayne produced a firearm, shooting Andrews and Caldwell.

Caldwell had been trying to help Andrews when he was shot, according to a sheriff’s department news release.

“I feel confident that our investigators have put together a strong case,” Sheriff Mike Stone said in the release. Stone thanked the Grambling State University Police Department, the Grambling Police Department, the Monroe Police Department, the Ruston Police Department and the Louisiana State Police for their roles in the investigation.

Richard J. Gallot Jr., the university’s president, thanked the authorities for “their around the clock effort in solving this case within the first 48 hours. Our thoughts and prayers continue to go out to the Andrews and the Caldwell families during this difficult time.”

The shooting had shaken the campus, a small community of 5,188 students, where the death of Andrews was “truly a loss of a member of a family,” Gallot said in an interview. The shooting occurred during homecoming week, when the school, in the city of Grambling, sees a spike in visitors.

“It’s a horrible thing to happen on any day of the week, any week,” said Will Sutton, the university’s director of communications. “It’s particularly unfortunate that it’s homecoming week, an annual, joyful series of days, where we have people returning home to campus. . . . Nobody wants to return to something like this.”

Students had received emergency text messages from the university after the shooting, urging them to stay in their rooms overnight, school officials said. About a third of the university’s students live on campus.

Caviness was alerted to the shooting after receiving several calls on his cellphone from students. University officials said he often gives his cellphone number to students at the beginning of the semester and encourages them to call him with any concerns, rather than go through the police department.

It’s just one example of the closeness of the Grambling State community, said Gallot, the university president. He told The Washington Post that he wasn’t surprised by the outpouring of support for the victims’ families so soon after the shooting, as dozens of students posted condolences on social media as early as 2 a.m. Wednesday.

He said that Andrews especially loved being part of the university’s family and that even the cafeteria workers were fond of him, adopting the senior as “one of their own.”

“I honestly can’t remember the last time there was a loss of life in this manner . . . the last time we had something of this magnitude,” Gallot said. “We’re not in the middle of a major metropolitan area. We’re a small community. Something like this is not something that happens every day.”

In a statement to the campus community, he asked that the “GramFam” student body do what it has always done: Look out for one another. The university will move forward with academic and event schedules as planned this week, including all homecoming events. Students and staff should expect an increased police and security presence on campus, Gallot said.

Andrews lived with his older brother, Ladarius Heard, in Ruston, La., a short distance from campus.

Heard, a contractor for an industrial building company, had been staying in Shreveport for an extended job assignment last week — but drove back to Ruston on a whim Friday night.

“I don’t know what it was,” Heard told The Post. “Something that told me to drive back.”

Earl Andrews, right, with his brother, Ladarius Heard. (Courtesy of Ladarius Heard)

He said he was sleeping when a friend called him around 12:30 a.m. Wednesday to alert him to the shooting on campus.

Heard said he can’t fathom why anyone would have wanted to harm his younger brother.

“He was always smiling, dancing,” Heard said. “He didn’t bother nobody.”

Andrews was studying criminal justice at Grambling, Heard said, and had planned on moving to Texas after graduation.

His mother, Juanita Augman, said he wanted to be a parole officer.

“I just can’t explain it,” Augman said of her son’s death. “It’s just been the longest, longest day. He was a wonderful child.”

He played football at Patterson High School, about four hours south of Grambling, and wanted to play in college but couldn’t because of an injury, she said.

He enjoyed basketball as well, and often played at the campus gym with members of Grambling’s basketball team. Andrews was also a runner and had earned more than 15 trophies during his time on the Patterson High School track team.

He eventually moved, transferring to Farmerville High School, not far from Grambling. He graduated from that school in 2013.

“He was a very active person. Everybody loved him,” his mother told The Post. “And he was very respectable.”

She added: “I love all my kids, but he was just a special one — everybody loved him.”

Grambling State was founded in 1901 by a group of black farmers and has become well known for its marching band and its football dominance; about 200 players went on to the NFL during the tenure of a legendary coach.

Susan Svrluga contributed to this report, which has been updated.