The Oklahoma City mom and runner has been missing since Tuesday. According to friends, she talked to a co-worker at 11:30 a.m. Tuesday and has not been seen or heard from since.

Driskill, 34, is Native American. She has dark brown hair and eyes. She is 5-foot-7 or 5-foot-8, 150 pounds, and she has a clock tattoo on the upper part of her left arm.

Driskill has run more than 30 marathons, and in 2011, she ran the Oklahoma City Memorial Marathon while seven months pregnant with her daughter. Working as a research assistant in one of the labs at the OU College of Medicine, she drew on medical expertise of those around her to be safe throughout her training and race day.

“Somebody at work asked me when I was getting a handicap permit,” she said at the time. “I said, ‘I'm not broken. I'm pregnant.'”

People saw that spunk again from Driskill these past few years at the Memorial Marathon. Two years ago, she and running friend David Bach realized they hadn't trained enough for the race, so they decided to have some fun. They dressed up in unicorn costumes.