Gilyard’s background was dysfunctional; his father, Lorenzo Gilyard (February 24, 1927 – October 24, 1999) was convicted of rape in 1970, his brother Darryl E. (also Daryle born February 12, 1953) and his brothers friend. He was convicted of a drug-related murder in 1989 and sentenced to life without parole, and his sister, Patricia D. Dixon (born July 20, 1958), a sex worker, was convicted of the murder of a customer in 1983 and served a 10-year sentence. In his younger years, Gilyard was known to bully and sometimes beat women.

Gilyard was a convicted child molester, having raped the 13-year-old daughter of a friend. Probation records show that from 1969 to 1974 he was suspected of five rapes, but was never convicted. Gilyard became a suspect in 1987 in the murder of Sheila Ingold. A crime lab later linked all 13 victims to one killer using DNA testing. A blood sample Gilyard provided in the 1987 investigation led to the murder charges.

In addition to the 13 known victims, authorities are also determining a link between Gilyard and Paula Beverly Davis, 21, who disappeared in 1987.

Of his known victims, 12 were murdered between 1977 and 1989. After living with Jackie Harris for a short time in Missouri and Los Angeles, they were married in Las Vegas, Nevada, on May 29, 1991, after which he and his wife returned to Los Angeles for over a year. Shortly after his return to Missouri, he murdered his 13th known victim. There have been no attempts yet to tie him to any killings in the Los Angeles area during his various stays between 1987 and 1992, and it is assumed that he stopped killing in 1993.