Kevin Roper of Jonesboro, Georgia, was behind the wheel of a Walmart truck early Saturday, when police say he caused a six-vehicle pileup on the New Jersey Turnpike.
In a criminal complaint obtained by PEOPLE on Monday, New Jersey State Police say Roper, 35, drove "without having slept for a period in excess of 24 hours."
New Jersey State Police
Roper now faces charges including vehicular homicide, auto assault and reckless driving. He is expected in court on Wednesday.
In a statement Saturday, Walmart president and CEO Bill Simon said that "if it's determined that our truck caused the accident, Walmart will take full responsibility," adding that road safety is "our absolute highest priority."
"This is a tragedy and we are profoundly sorry that one of our trucks was involved. We are working quickly to understand what happened and are cooperating fully with law enforcement to aid their investigation," he said.
Morgan, 45, remains in critical condition but is more responsive after undergoing surgery Sunday, progress his rep called "an incredibly encouraging sign."
With reporting by DIANE HERBST