The reason "why did D4vd do it" is presently unclear based on publicly available information. D4vd, whose real name is David Anthony Burke, is under investigation by authorities after a decomposed body of a teenage girl, Celeste Rivas, was found in the front trunk of a Tesla registered to him. The circumstances surrounding how the girl died and ended up in the Tesla are still being investigated, and the cause of death is not determined. D4vd is reportedly fully cooperating with law enforcement as they continue their probe. No charges or explanations related to motive or intent have been publicly disclosed as of now. Authorities have not confirmed homicide or any reason for why it happened, and it remains an open investigation.
In summary, there is no confirmed public explanation for why D4vd would have done anything related to this case; the investigation is ongoing and facts are still emerging.