-- Editor’s note: ABC News’ original posting of this story on March 16, 2016, has now been updated to reflect authorities’ determination that the lawsuit is a hoax.
The $10 million lawsuit thought to have been filed by Kalamazoo, Michigan, shooting suspect Jason Dalton against Uber is a hoax, according to local authorities.
"We have confirmed there is no way Jason Dalton wrote or had this lawsuit written," Kalamazoo County Undersheriff Paul Matyas told ABC News today. "Dalton himself denies having anything to do with it."
The handwritten complaint, which blamed Uber for Dalton's mental breakdown, was filed properly with the court and verified by a judge’s clerk in Detroit. It also listed Dalton's correct inmate number.
However, the postmark on the envelope in which it was sent reads Philadelphia, but the mail out of the Kalamazoo jail where Dalton is housed is sorted in Grand Rapids, Michigan, Matyas said.
"The letter was mailed in Philadelphia," Matyas said. "The handwriting was confirmed as not being his. This was a hoax."
Dalton, a former driver for Uber, is accused of going on a deadly shooting rampage that left six people dead and injured two.
In the fake complaint, Dalton appeared to demand $10 million from Uber in punitive damages, blaming the transportation company for the shooting spree of which is he accused.
"I worked years as a Uber contractor and they ripped me off, never paid me back wages or overtime," the fake complaint, dated March 11, reads. "I busted my butt for them."
The fake complaint describes the car service company as a "hostile workplace environment" that treated Dalton like a second-class citizen.
"Uber treats their drivers like crap," the fake complaint said.
Before the complaint was revealed to be fake, Uber responded to the suit in a statement, saying Dalton refuses to take responsibility for his own actions.
"It's hard to know how to respond to someone who refuses to take responsibility for his own actions," the statement read. "Our hearts go out to the victims' families who have to live with the consequences of his terrible crimes."
The fake complaint also said that Uber discriminated against Dalton's "mental health" and that the company "ruined" his life.
"I'm currently in prison because of Uber," the fake complaint said. "My wife is divorcing me because of Uber."
At the end of the fake complaint, the writer expresses a wish for the lawsuit to be tried in front of jury. It was signed, "Respectfully submitted, Jason Brian Dalton."
Dalton, a Kalamazoo resident, was arrested on Feb. 21 after allegedly going on a shooting rampage in three separate incidents the day before. He was charged with six counts of murder, two counts of assault with intent to commit murder and eight charges of using a firearm during the commission of a felony. A "not guilty" plea was entered on Dalton's behalf by the judge at his arraignment, according the prosecutor assigned to the case.
Dalton later told police that he believed the Uber app was controlling him.
"... It feels like it is coming from the phone itself, like an artificial presence," Dalton told investigators, according to a police report obtained by ABC News.
A spokesperson for Uber refuted that statement. "Drivers decide what they want to do with the app," the rep told ABC News.
Dalton's attorney, Eusebio Solis, was not aware of the $10 million lawsuit, he told ABC News Wednesday. He has not commented since the suit was revealed to be a hoax by authorities.
Earlier this month, Dalton's defense attorney had requested, and a judge ultimately ordered, that Dalton undergo an examination to determine whether he is mentally competent to stand trial.
It is not clear who filed the fake complaint.
ABC News' Shahriar Rahmanzadeh, Esther Castillejo and Michael DelMoro contributed to this report.