KALAMAZOO, MI -- The National Transportation Safety Board is investigating the Kalamazoo bicycle crash that killed five people and injured four.

Officials with the NTSB confirmed Friday the agency is investigating the crash, and said its team already is in Kalamazoo.

NTSB spokesman Eric Weiss said the team will look at all aspects of the incident, including how it happened and how the truck hit the bicyclists. He said the team will reconstruct the crash and find out if there are any safety issues that could be improved, from the vehicles involved to the road.

Weiss said the NTSB is investigating because the agency has taken an interest in the case, and not at the request of local authorities.

"This is such a singular event that we wanted to look at the issues behind it," said Weiss, who acknowledged it's unusual for the NTSB to investigate crashes involving bicycles.

The board is an independent federal agency charged by Congress to investigate every civil aviation in the U.S. and significant accidents in other modes of transportation. The board determines the probable cause of accidents and issues safety recommendations to help prevent future ones.

Weiss said the investigation could take up to a year or more. The team has the option to issue a report or a brief on the case, which would be publicly available, he said.

Charles Pickett Jr., 50, of Battle Creek, is facing five counts of second-degree murder and four counts of reckless driving causing serious impairment of a body function in the crash. Police say three different jurisdictions got calls about Pickett's erratic driving in the half hour leading up to the crash.

Authorities say he was driving a Chevrolet pickup truck that hit nine bicyclists from behind on North Westnedge Avenue near Markin Glen County Park in Cooper Township just after 6:30 p.m. Tuesday. Pickett was found near the scene outside of his vehicle.