Police in Michigan have arrested a man suspected of plowing his pickup truck into a group of bicyclists, killing five of them and seriously injuring four others Tuesday evening in Cooper Township.

The driver left the scene, but a suspect, described as a 50-year old man, was apprehended a short while later, according to law enforcement.

The names and ages of the victims have not been released. All were reportedly adults.

As Michigan Radio's Lindsey Smith reports for NPR's Newscast unit:

"Kalamazoo County Prosecutor Jeff Getting says police received calls about the blue pickup driving erratically shortly before the crash. ..." 'We don't have any motive for why this happened. As far as I know, the bicyclists were not doing anything other than simply riding their bikes in a proper way along the road.' "

A man who said he witnessed the incident just a few miles from Kalamazoo, told WOOD-TV that the truck was moving erratically and almost hit him. He said he didn't have time to warn the cyclists.

"I saw a bunch of bikes hit the front of his truck and a couple of them flew," Markus Eberhard told the TV station.

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