In People v. Enriquez (1977) 19 Cal.3d 221, the prosecution's sole efforts to secure the presence of a 17-year old witness was to ask the trial court to issue a bench warrant and make a single inquiry to the witness's mother about his location. (Enriquez, supra, 19 Cal.3d at p. 236.) Because the prosecution failed to take obvious steps to find the witness -- for example, to look for him at his school and at his mother's home -- the Supreme Court found an absence of due diligence. (Ibid.)