OKLAHOMA CITY - The fatality crash involving an ambulance is now being investigated as a homicide.

That crash happened last month near SW 59 and Interstate 44 and that driver showed compelling signs he may not have been fully awake at the time of the crash. 

According to police documents, witnesses said they saw the St. Anthony ambulance was speeding and swerving, likening it to behavior of a drunk driver. 

That driver was 34-year-old Matthew Erickson. He was taking 66-year-old Carolyn Koch and and another woman to the hospital when it veered off the road. The crash killed Koch and seriously injured the other woman. 

That woman told investigators she could feel the ambulance swaying and hitting the rumble strips on the side of the road before the crash. At one point she told Erickson to stop driving that way saying "it was not funny."

Investigators also learned Erickson's partner for the evening had expressed concerns about transporting patients because she was unable to keep Erickson awake during the overnight shift after repeatedly telling him they had calls to help patients. 

It also wasn't the first time concerns were raised about the driver. Just days before the crash, he had been taken off duty for failing to stay awake on the job.