Boomhower was last heard from when she spoke to a friend by telephone from her home in Los Angeles, California on August 18, 1949. The friend called her between 7:00 and 8:00 p.m. After the conversation was over, Boomhower changed clothes, leaving the old dress on her bed, and left her home. She left her car locked and parked in the garage, and an uneaten salad on the dining room table. All the lights were left on as well. She has never been heard from again. She had many social engagements scheduled for the week of her disappearance and missed them all without notifying anyone, which is uncharacteristic of her.

Boomhower's white handbag was found in a telephone booth at a supermarket in Los Angeles five days after she disappeared. On the side of the purse someone had written a message in ink: "Police Dept.—we found this at beach Thursday night." Thursday was the day of Boomhower's disappearance. The purse contained a credit card, Boomhower's driver's license, her car keys, her compact and her lipstick. There no evidence that the purse had been exposed to sand or water. This was the last known trace of Boomhower.

Boomhower's husband, a linoleum tycoon and big game hunter, died six years prior to her disappearance. She is described as a very social, fun-loving woman. She gave the appearance of a wealthy individual, but in fact she was having financial problems at the time of her disappearance. When she was declared legally dead seven years after her disappearance, her estate was appraised at only a minimal value. Authorities believe Boomhower was murdered, but the circumstances surrounding her disappearance are unclear.