Police have charged 18-year-old Jordan Baker, 19-year-old Jonathan Myles and 21-year-old Kaylnn Ruthenberg in Jones' death. They all face felony murder, aggravated assault and armed robbery charges.

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Police said Jones was robbed and shot when he responded to a Craigslist ad about an iPhone 6 for sale.

"As the victim approached Jamaica Cove and entered in to meet with the sellers for the iPhone, the suspects then robbed, shot and killed him right at the scene," Officer David Baldwin told WSB-TV's Ross Cavitt.

The case hits home for Cobb County. Bud and June Runion were recently killed in central Georgia while responding to a Craigslist ad for a classic car.

"Obviously, there have been two cases where this has really turned tragic for somebody just wanting to buy something on the Internet," Baldwin said.

Brenard Williams, captain of the football team at CAU, said he knew Jones well. He showed WSB-TV's Rachel Stockman the last text that the two exchanged, talking about football.

“He was a great man – well-dressed, humble; he really represented the school well. I’m just sad he had to leave this way,” Williams said.

“It’s a shame it had to happen. I’m sure he didn't go out there expecting that would be his last move for life,” another student said.

Clark Atlanta University emailed its students Tuesday afternoon about Jones' death:

"Clark Atlanta University today mourns the death of junior chemistry major James E. Jones, a native of  Daytona Beach, Fla., who maintained a cumulative 3.0 GPA. Mr. Jones was killed [Monday] while visiting Marietta, Ga. In a show of respect to his family and close friends, the university will first reach out to these individuals before finalizing any memorial tributes. Details for a memorial service are forthcoming.

"This is a devastating loss for the Clark Atlanta University family. Mr. Jones was a serious scholar and a kind, engaging spirit whose work and comportment spoke well of the university's core values and those long ago instilled in him by those contributing to his upbringing. In addition to his studies, he was a UPS Scholar at Fickett Elementary School and a science mentor for the HBCU Rising Cares Mentoring Program at Brown Middle School. He also was an amateur athlete.

"Please keep Mr. Jones, his family and close friends and the CAU Chemistry Department in your thoughts and prayers as you go about your routines this afternoon.

"Details on the university's plans to remember Mr. Jones will be announced later this week."