A few days into her boyfriend’s disappearance, Ronique Green, an 18-year-old criminal justice major, began doing some of her own detective work.

Sick with worry, she began posting desperate pleas for information concerning 19-year-old Jmaal Malik Keyes on his and other friends’ Twitter accounts. When she found the metro Atlanta man’s contact list online in iCloud, she started dialing up his friends and his fellow students at Middle Georgia State College. She reached Robert Kane Rolison on May 5.

Green said Rolison told her that he had transported Keyes, who did not have a car, to a house about 15 minutes away from the Middle Georgia State’s Cochran campus on the last day he was seen. But something about his story of dropping off Keyes didn’t add up for Green.

Her suspicions may have been correct.

Police arrested 17-year-old Rolison — a classmate of Keyes — on Thursday night and booked him with Keyes’ murder, even though they have not recovered a body.

Authorities have not released a motive for the killing or said how they believe Keyes died. He was last seen April 25 leaving his dormitory. Few details were available Friday about the relationship between the two teenagers, except that Keyes and Rolison are believed to have socialized on campus.

Officers from several law enforcement agencies searched Friday afternoon for Keyes’ remains along the Ocmulgee River in Hawkinsville, where Rolison is from. The area is about 10 miles southwest of the college and 120 miles south of Atlanta.

The campus police chief told WMAZ-TV in Macon that Rolison may have driven Keyes to a convenience store on the day he disappeared.

“That was the story we were told, it just hasn’t been confirmed with eyewitnesses,” Chief Shawn Douglas said.

Green said she hoped to one day marry Keyes, whom she described as a sweet guy who regularly attended church. She said he was “big on church” and “big on family.” She said the criminal justice major dearly loved his mother and sister and wanted to be like his older brother.

Green, who lives in metro Atlanta and is a student at Georgia Highlands College, said she became concerned about Keyes a day after he disappeared. She called and his phone went straight to voicemail.

“I knew something was up,” Green said.

According to a press release issued by the college, Rolison was dual-enrolled at a local high school and at Middle Georgia State.

“We are absolutely devastated by this news,” John Black, the college’s interim president, said late Thursday. “There are no words to describe how deeply hurt we are and how terrible we feel for Jmaal’s family.”

About 20 people from Keyes’ Austell church went to Cochran on Wednesday to help in the search. Destiny World Church had also posted a $3,000 reward for information leading the the teen’s safe return.

The church’s pastor, Wilbur Purvis, called the arrest “very shocking. Of course, we were very hopeful and optimistic that we would get better news.”

Purvis said Keyes, who graduated from Hiram High School in Paulding County, had been a part of his church for the past 10 years and was “very active in our church, very loving, a very kind young man.”

Purvis said the missing teen’s older brother graduated from college this week with a degree in criminal justice “and from what I remember, he wanted to follow in his brother’s footsteps, and we were very hopeful that he would do great things in life.”

He said the news has shocked the church community.

“Never in 20 years of pastoring have I experienced this kind of grief in our church,” Purvis said.

Purvis said that, while Keyes’ mother was “very devastated” by the news of an arrest, “her faith is still intact. She was very adamant when she spoke to her children about not being bitter, not being angry, accepting this as something that has occurred and believing that her faith in God will get her through.”

Meanwhile, Rolison is being held without bond at the Bleckley County Law Enforcement Center.

Todd Lowery, agent in charge of the GBI’s Eastman office, said he could not confirm that Rolison gave Keyes a ride. He also would not say whether Rolison had offered a location where Keyes’ body might be found. The search of the river was complicated Friday by the swollen waters of the Ocmulgee, which is above full pool.

“We don’t have a concentrated search at this time,” Lowery said. “We’re just following leads, going to the obvious places that the public can access.”

- Reporter Mike Morris contributed to this story.