Authorities say a lawsuit against Uber filed in the name of a driver accused of gunning down six people between picking up fares is bogus.

Kalamazoo County Undersheriff Paul Matyas said Thursday that he saw reports about a handwritten lawsuit by Jason Dalton seeking $10 million from the ride-hailing service and became suspicious because the envelope it reportedly was mailed in had a Philadelphia postmark.

Matyas says Dalton, who is jailed, denied filing the lawsuit and that the handwriting doesn't match Dalton's.

The lawsuit was listed in federal electronic records as being filed by Dalton in U.S. District Court in Detroit and was given a case number.

Dalton is accused of fatally shooting six people and wounding two others Feb. 20 between picking up passengers in Kalamazoo.