(2023) Library of Congress does not distinguish this Hector Garrido from a music composer/arranger, perhaps not from others who share the name. Thus WorldCat (above) conflates them, too. LC does report interior illustrations by "Hector Garrido" for some of the Susan Sand mystery stories by Marilyn Ezzell.
Garrido studied art in Buenos Aires, Argentina, and began professional work in the United States during the 1950s (Flickr.com).