By Chanteé Lans

YEADON, Pa. (CBS) — It was an arrest more than three years in the making. Police have solved the cold case murder of a high school football player.

Eighteen-year-old  Zion Vaughan, a Penn Wood High School linebacker, was gunned down and robbed on Dec. 8, 2016, near his home near the corner of Bullock and Parmley Avenues.

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The case went cold until now. Police charged 22-year-old Rodney Gary, of Lansdowne, last week.

“During the course of the investigation, officers developed video where we were able to come up with two suspects,” Yeadon Police Chief Anthony Paparo said.

Those two suspects were seen walking on Church Lane around 8 p.m.

The man on the right is then 19-year-old Gary. The man on the left is a second suspect who is already in prison in North Jersey on separate federal and robbery-related charges.

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The business security camera, which Yeadon police released in December of 2016 to the public, captured them in an exchange with Vaughan.

“They’re talking and that’s the shadows you see,” Paparo said.

Vaughan, on the left, then turns around to show the suspects that he received their phone call and has their number.

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He then walked into a store with a friend.

About an hour later, police say Vaughan met up with the two suspects again, was robbed of his phone and shot once in his back as he tried to run away.

“During the course of continued diligent police work involved in this matter, they continued to beat the street and hit the street and interview additional people,” Paparo said.

Police say Gary confessed. He will be arraigned on homicide, robbery and related charges.

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Delaware County District Attorney Jack Stollsteimer had a message for Vaughan’s family.

“The best thing we can say today is the family of the victim is here with us today. They are beginning to see, I hope, the first step for finding justice for Zion,” Stollsteimer said.

Vaughan’s family declined to speak on camera but a Penn Wood High School coach said he’s relieved an arrest has been made.

The DA’s office says Gary will be arraigned by video on Thursday.