Cales was last seen at approximately 4:30 p.m. on March 11, 1998, in the vicinity of the 2300 block of west 199th Street in Blue Island, Illinois. She was carrying a Bible and her purse at the time. She said she was going either to church or to a friend's house (accounts differ), but she never arrived at her destination and has never been heard from again.

Cales has six children. Two of them died in the 1980s, one in a fire and one of natural causes. Cales was reportedly devastated by the loss of her children. She and her husband divorced in 1990 after a troubled marriage, and he got custody of their surviving children. She had also been arrested multiple times for offenses such as shoplifting, driving while intoxicated, battery and criminal property damage, and regularly failed to appear in court as scheduled. Coincidentally, in 2007, eleven years after Cales disappeared, her daughter Stacy Peterson also vanished and has never been found. The cases are not believed to be connected in any way.

Cales had a history of dropping out of sight for weeks at a time, but she has never been gone for this long. Few details are available in her case.