Born in Puerto Rico in 1934, Carmello DeJesus relocated to the mainland United States, where he developed a reputation as a gambler and career criminal with a volatile temper. His criminal record, dating back to 1960, included convictions in New Jersey and Florida for offenses such as burglary, gambling, possession of stolen property, assault, and two prison escapes.

DeJesus's first known murder occurred on September 17, 1971, in Bridgeton, New Jersey. He broke into the home of his girlfriend, Octavia Ford, and during a confrontation, shot her in the chest, resulting in her death. He fled the scene, abandoning his car near Woodstown and stealing another vehicle to escape.

Between 1971 and 1973, DeJesus committed at least three more murders, including those of Sandra Postell, 30, and Milagro Tena. Details about the fourth victim remain unknown, as DeJesus did not provide identifying information.

On September 8, 1973, DeJesus was found dead in a field near Perinton, New York, by two teenagers. He had died from a self-inflicted gunshot wound to the chest. A Spanish-language Bible was discovered near his body, containing a suicide note in which he confessed to the four murders, stating his desire to prevent further killings by ending his own life.