Carpenter was last seen in Denton, Texas on June 1, 1948. She left her home in Texarkana, Texas and took a train to Denton, six hours away. At the station she took a taxicab to Texas State College for Women, now called Texas Women's University. She was planning to complete a summer term there. Carpenter had been a drum majorette in high school and was taking science courses in college; she aspired towards a career as a nurse or a laboratory technician. She was active in the Baptist Church in 1948.

The cab driver, Edgar Ray "Jack" Zachary, later stated he stopped in front of Brackenridge Hall at 9:00 p.m. and Carpenter gave the driver a ticket for her trunk and paid him a dollar so he would fetch it for her from the train station the next day. After getting out of the cab, Carpenter approached two young men standing near a yellow or cream-colored convertible car, possibly a Pontiac. One of the men was tall and the other is described as "chunky." Carpenter appeared to know them and began to speak to them, and the cab driver drove away. She never checked into her dormitory, Brackenridge Hall, and has never been heard from again. She was carrying a red bag at the time of her disappearance.

Some of Carpenter's former boyfriends stated she became infatuated easily and speculated she ran away with a lover, but her family did not believe she would have left without telling them. Carpenter's boyfriend passed a polygraph in connection with her disappearance, but authorities learned Zachary had a record for petty crimes and a reputation for being abusive. He was charged with attempted rape in 1957, but the charge was dropped after the victim asked authorities not to prosecute. Zachary's wife stated he had been home with her from 10:00 p.m. onwards on June 1, but ten years after Carpenter's disappearance, his wife told police she had lied to them and her husband had not actually arrived home until 2:00 or 3:00 a.m. on June 2. Zachary died in 1984. He was never charged in connection with Carpenter's case, but he remains a suspect, although he passed two polygraphs in her case.

In the winter and spring of 1946, five young people were murdered in lovers' lanes in Carpenter's hometown of Texarkana. The crimes are believed to have all been committed by the same person. The murderer was never caught and became known as the Texarkana Phantom Killer. Carpenter was acquainted with three of the victims. Authorities investigated to see if there was a link between her disappearance and the Texarkana slayings, but they found no evidence to support this theory.

In 1998, authorities received a tip that two men had raped and killed Carpenter shortly after her disappearance and buried her body in a dam at a stock tank near the Texas Women's University campus. The suspects were both deceased by 1998 and were not publicly identified. Authorities searched the dam after receiving the information, but uncovered no evidence.

Numerous leads and possible sightings of Carpenter have surfaced throughout the decades since her disappearance, but no evidence has been uncovered and none of the accounts have been proven. Her father died prior to her disappearance and her mother died in 1980, and she has no siblings, but three of her cousins still hope to get answers in her case. Carpenter's disappearance remains unsolved.