“Oh my God. He's in a little itty bitty pickup, OK? He's going down my street,” said Bryan, who continued to say it was a dark-colored pickup driving west.
The call ends soon thereafter when she says she has to go, as her husband gasped for air.
Keith Bryan, 52, died about 6 a.m. Wednesday at OU Medical Center in Oklahoma City.
Mustang police and the Oklahoma State Bureau of Investigation have not offered a description of the shooter more detailed than the one Becky Bryan gave on the 911 call. No suspects have been named, and no one has been arrested.
Mustang police have deferred comment to the OSBI on the case.
Brown and Mustang Police Chief Chuck Foley have said Becky Bryan is the only witness to the incident and investigators have spoken with her as they try to develop leads.
Officials have said it's possible the shooter was a disgruntled, unsuccessful job applicant.
The Nichols Hills Fire Department has not hired or interviewed anyone since 2007. The much larger Oklahoma City Fire Department hires frequently, and its chief, Keith Bryant, has a name similar to Keith Bryan's.
Oklahoma City fire officials heightened headquarters security in the wake of the shooting, though at the time Bryant was in Washington, D.C., for a conference.
Becky Bryan filed for divorce from her husband in January 2010. The divorce is still pending.
Efforts to reach Becky Bryan have been unsuccessful.