SYRACUSE, N.Y. -- When 21-year-old Silas Collier was murdered on May 12, 2007, the investigation immediately began to find the person responsible. 

Syracuse Police responded that night to the 100 block of Mark Avenue, where Collier had been shot inside a parked car in a driveway. At the time, police did not have enough information to make an arrest, so they continued investigating for the next nine years.

Tuesday, they arrested Alfred Thomas Jr., and charged him with second-degree murder and second-degree criminal possession of a weapon.

"Probably the best of it, if there is a best part, is notifying the family like I did this morning for Mr. Collier," Syracuse Police Detective John Nolan said. "It's probably the most rewarding part."  

Detective Nolan and the department's cold case squad took over the case in 2012. They reviewed and collected dozens of interviews. Police said Thomas and Collier knew each other, but did not disclose their relationship. They also found new evidence years after the shooting, including the believed murder weapon.

"We did link it, and we did confirm that it was the weapon used five years earlier to kill Mr. Collier," Nolan said.

With the evidence gathered, police said they felt confident they had enough for an arrest in Collier's death. A nine-year cold case is now closed.

"The families deserve closure, and we never stop working on these homicides," Chief Frank Fowler said. "We change our strategies a little bit, but we never stop working on them regardless to how old they are."

Detectives said they are working on 98 cold cases right now. In the past five years, they have shut the book on nine other cases.