The evidence was collected Friday in Hawkinsville. Testing later at the state crime lab determined they were human remains, the Georgia Bureau of Investigation said.
They were found in an area where a building burned around the time 19-year-old Jmaal Malik Keyes was last seen. DNA testing will be done to determine whether the remains are that of Keyes.
Keyes, a freshman from Austell, was last seen on the school's Cochran campus April 25. Investigators have not said how they believe he was killed.
Campus police said they have surveillance video that shows Keyes, who did not have a car on the campus, getting into another student's car, WXIA-TV in Atlanta reported. Officers located that student, who told them he dropped Keyes off in a neighborhood near campus April 25.
That's the last time anyone has reported seeing Keyes. Police said his belongings were untouched in his dorm room.
Keyes and the teenage suspect apparently knew each other as classmates, campus Police Chief Shawn Douglas told WMAZ-TV in Macon.
The suspect was "dual-enrolled" at his high school and the college. Investigators did not find any calls between the two on their cell phones, he said. The Associated Press generally does not identify juveniles who are charged with crimes.
The suspect is jailed in Bleckley County, and a date for his bond hearing has not been set, the GBI said.
Keyes had been very active at Destiny World Church in his hometown of Austell, just west of Atlanta. Keyes' older brother graduated from college this month with a criminal justice degree, and the teen wanted to follow in his footsteps, said Wilbur Purvis, a pastor at the church.
Sections of the Ocmulgee River were also searched on Friday, though it wasn't known whether any evidence has been recovered from that search.
Copyright 2013 The Associated Press.