What Set Off The Kalamazoo Uber Driver's Alleged Shooting Spree?

Shortly before the shooting spree that claimed six lives, an Uber passenger said he fled driver Jason Dalton's Uber car.

An Uber passenger says he fled a nightmare ride with accused Kalamazoo shooter Jason Dalton, who was charged with killing six strangers.

Read: Alleged Kalamazoo Shooter Was Uber Driver Who Picked Up Fares After Rampage: Report

Matt Mellen was riding in Dalton’s car before police say the 45-year-old went on a rampage Saturday, allegedly killing complete strangers at three different locations.

Mellen claims that Dalton got a call during his ride and told WWMT: “After that call, he started driving erratically, running stop signs. We were kind of driving through medians, driving through the lawn speeding along and then finally, once he came to a stop, I jumped out of the car and ran away."

He called 911 and his fiancé even posted a warning on Facebook:

BREAKING: We've talked to woman who posted about bad Uber driver before shooting. Doesn't want to comment right now. pic.twitter.com/XLyF9cPCrW

— Luke Stier (@LukeStier) February 21, 2016

The horror began Saturday at a Kalamazoo County apartment complex, where police say Dalton shot a woman multiple times around 6 p.m. Fifteen miles away, a father and son were shot dead about four hours later as they shopped for a car at a dealership.

Minutes later, a hail of bullets in a nearby Cracker Barrel restaurant parking lot left four dead and a 14-year-old girl "gravely injured" in two separate cars, authorities told the AP.

Dalton, a father of two, was arrested soon after midnight Sunday after his car was spotted by a deputy. He is set to be arraigned Monday afternoon. 

Read: Cops: 'Jealous' Husband Arrested After Trying to Shoot Wife Breastfeeding Their Newborn

Police say he continued to pick up Uber passengers between shootings. Carmen Moren and Dillon Thompson were scheduled to be picked up by Dalton but changed their plans.

“We decided to cancel the Uber and then three minutes later we decided to take a different Uber. I think honestly god was watching over us kept us safe, kept us out of that situation,” she said.

Thompson said: “A difference of three minutes that could have altered our lives completely or taken it away from us.”

There was an emotional vigil for the victims at a church in Kalamazoo on Sunday.

Watch: Doctor Who Attacked Uber Driver Lives in Fear: I'm Getting Death Threats