Kalamazoo Shooting: Lawsuit Against Uber Allegedly Filed by Suspect Is Hoax

A handwritten federal lawsuit reportedly filed by the suspect in last month's deadly shooting rampage in Kalamazoo, Michigan, was a hoax, officials said Thursday.

The suit was mailed Tuesday to the U.S. District Court in Detroit, The Associated Press reported, and claimed alleged shooter Jason Brian Dalton was suing Uber for $10 million after failing to get back wages and overtime as a driver for the ride-hailing app.

But the complaint is a sham, Kalamazoo County Undersheriff Pali Matyas told NBC affiliate WOOD-TV in an email that was also confirmed to NBC News.

Listen to 911 Calls from Night of Kalamazoo Killings 3:45

"I was suspicious last night when I saw the envelope the lawsuit came in was postmarked Philadelphia," Matyas said. "We investigated and Dalton did not send it, did not authorize it and does not know who sent it. Further it was not his handwriting and it is not a jail envelope."

Dalton, 45, remains jailed after he was charged with killing six people and wounding two others as he picked up passengers for Uber on Feb. 20. In an interview with detectives, Dalton allegedly said the car service turned him into "a puppet" and that "he could only tell us that (the app) has the ability to take you over."

Uber, in an initial response Wednesday to the fake lawsuit, said in a statement that "it's hard to know how to respond to someone who refuses to take responsibility for his own actions."