I think you are referring to the famous auto de fe of Maní organised by Fray Diego de Landa, where not only the Mayan codices were burnt, but also many statues, idols, and any lithurgical implement Fray Diego and his enforcers could get their hands on. The motivation, as you comment, was religious, the idea being to suppress pagan religious practices, that 50 years after the conquest were still very prevalent in the Yucatán peninsula.

When the exploration of America and its conquest started, the Spanish monarchs were under the obligation to christianise those new territories, as clearly stated by the Inter Cetera papal bulls, which were incorporated into the common practice of evangelisation of the Indies. This crystallised in the Spanish laws such as the Laws of Burgos from 1512, ratified and expanded in 1513 in Valladolid. One of the obligations the encomenderos had was to evangelise the natives, as well as teach them to write, read, and the "four rules" (addition, substraction, multiplication, and division). Failing to fulfill these duties, or mistreating the natives, resulted, as per the laws, in the loss of the encomienda, complete withba fine of 50 ducados per native affected. These obligations made sense in context, as the new christians would be full subjects of the Crown, with the same rights and duties as anyone from Castile. We can describe the encomienda as a transitory regime towards a late feudal or early modern society.

Back to the point, Fray Diego de Landa was extremely thorough in suppressing pagan practises, not only out of a sense of fulfilling the duties he had, but also because he had been very influenced by the teachings of Cardinal Francisco Jiménez de Cisneros. This cardinal had been this thorough in the Kingdom of Granada, to the point of organising a massive bonfire of books in Arabic in order to eradicate Islam from Granada, as Fray Hernando de Talavera's efforts in converting people through reasoning, good will, and charitable works had proved to be not very fruitful. Cisneros opted for a stronger approach, confiscating all the books in Arabic he could and burning them, except for the books on medical matters, which he took and transferred to the university he had recently created in Alcalá de Henares.

Landa, in the spirit of Cisneros, burnt anything heretic. However, being an intellectual and a curious man, he annotated many of the drawings and hieroglyphs from the Mayan codices, which were later useful in deciphering the very few surviving Mayan codices, as well as the Mayan inscriptions. Other Spanish scholars of the next century had a lot of interest in Mayan language and compiled grammars and vocabularies of the language, but transliterated into Spanish writing customs.

As for the sources of information, Diego de Landa himself wrote a "Relación de las cosas de Yucatán", wheee he gives a detailed account of all of this. There is also the juicio de residencia or process he was subject to after his tenure, where many more details are consigned.

I shall also recommend other Spanish sources about the conquest and evangelisation of America, such as Gonzalo Fernández de Oviedo's "Historia General y Natural de las Indias" (1535), Bartolomé de las Casas' "Historia General de las Indias" (1559), and José de Acosta's "Historia natural y moral de las Indias (1590). They also contain the impressions the Spanish had on the cultures they encountered.

As for primary sources on the Spanish laws for America, there is the massive "Cedulario Indiano" or "Cedulario de Encinas", from the very late XVI century, accessible online in a very good edition published for free in the BOE (State's Official Bulletin). This cedulario or legal compilation contains every single law or ordinance that concerned the Spsnish America.

Sources:

Landa, Diego de (1566), Relación de las cosas del Yucatán. Modern edition by the Association of Mayaists, here.

Fernández de Oviedo, Gonzalo (1535), Historia General y Natural de las Indias. Modern edition by José Amador de los Ríos (Madrid: BAE, 1959). Digitisation of the princeps edition, here.

Casas, Bartolomé de las (1559), Historia general de las Indias. Modern edition available in Biblioteca Virtual Miguel de Cervantes. Digitisation of the manuscript, here.

Acosta, José de (1590), Historia natural y moral de las Indias. Modern edition by Fermín del Pino (Madrid: Consejo Superior de Investigaciones Científicas, 2008). Digitisation of the princeps edition, here.

García Oro, José (2002), Cisneros: El cardenal de España. Barcelona: Ariel.

Morley, Sylvanus Griswold (1915), An introduction to the study of the Mayan hieroglyphs. Washington: Government Printing Office. Available on Project Gutenberg, here.

Oroza Díaz, Jaime (1984). Historia de Yucatán. Mérida: Ediciones de la Universidad Autónoma de Yucatán