The two were booked at the LAPD's Parker Center headquarters for the attempted murder of 27-year-old Roberta Dos Santo Busby.
Busby was doused with gasoline and set on fire at about 1:30 a.m. last Thursday. She suffered burns on over 60 percent of her body.
Busby, a mother of two, is in critical condition at the Grossman Burn Center. She has undergone the first of several skin grafts.
Petrillo is being in held in lieu of $500,000 bail, and Theriault-Odom is being held without bail, according to the Los Angeles County Sheriff Department's Web site.
City News Service contributed to this story.
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