JACKSONVILLE, Fla. -- Robert "Bobby" Nixon was returning from the Jacksonville Sheriff's Office Light the Night Charity Ride on his motorcycle last Friday when he was thrown from his bike and killed.

Nixon, who was wearing a helmet, was about a mile away from his home, just off Yellow Bluff Road, when he suddenly stopped short. Skid marks and cracks in gravel still mark the place where he slammed on his brakes and was thrown from the bike.

The accident happened directly in front of the Eagle Hammocks subdivision. So far, no witnesses have come forward, but there's plenty of talk among neighbors.

"Possibly somebody came out of the subdivision here in Eagles Hammock and possibly didn't stop," said Jim Hardy, Nixon's friend and neighbor.

Police said it wasn't a hit-and-run crash, but there's a good chance someone rolled through a stop sign at the same time Nixon was approaching.

"Could be that they never even saw him," Hardy said.

Nixon's nephew Malcolm Farmer, a retired JSO officer, said that Nixon often rode his motorcycle and recently took a 7,000-mile trip out west. He said his uncle was a safe driver.

"I've ridden with him many times, and he's one who would always drive the speed limit," Farmer said.

Nixon, 64, was a retired JEA employee. He leaves behind a son who's also a JSO officer.

The family said they want to know what happened that night so they can have closure.

"The family's not going to be out for blood, I don't think," Farmer said, "but we just need to get it resolved as to what happened, if anyone can help us figure it out."

If you have any information about the accident, you're asked to call Crimestoppers at 866-845-TIPS. You can remain anonymous, and you may be eligible for a cash reward.