DETROIT (AP) — A Michigan prosecutor filed murder charges on Thursday against the 50-year-old driver of a pickup truck that struck a group of bicyclists, killing five of them and seriously injuring four others.

Kalamazoo County Prosecutor Jeffrey Getting charged Charles Pickett Jr. of Battle Creek with five counts of second degree murder and four counts of reckless driving in the crash Tuesday in Cooper Township north of Kalamazoo. Pickett will be arraigned as soon as his health permits, the prosecutor said.

The bicyclists ranged in age from 40 to 74 and were part of a group that called themselves "The Chain Gang." They were five miles into a weekly 30-mile ride when they were struck from behind on a road in the western Michigan countryside.

Police said they had received complaints about a pickup being driven erratically and were searching for it minutes before the crash around 6:30 p.m. on the two-lane road.

The driver fled on foot but was caught by police shortly afterward. He remains in custody.

Getting said police are continuing to gather information on what led to the crash and the charges on Thursday were the first step in the legal process.

Mark Rose, who co-founded The Chain Gang about 15 years ago, said its members weren't "hardcore," but biked regularly for the exercise, enjoyment of being with friends and the "safety in numbers." He said he dropped out several years ago to focus on running.

"They were just casual cyclists who enjoyed the ride," said Rose, 58, of Galesburg.

Killed in the crash were Debra Bradley, 53, Melissa Fevig-Hughes, 42, Fred Nelson, 73, Lorenz Paulik, 74, and Suzanne Sippel, 56. The injured bicyclists were Paul Gobble, 47, Sheila Jeske, 53, Jennifer Johnson, 40, and Paul Runnels, 65.