Holden was a Bladerunner who's abilities was comparable to Richard Deckard. Holden took up the job to test knew people coming to work for Tyrell corporation after the Replicants attempted to brak in. On one of these days, he actually got a replicant. He first asked the man aboutwhy he was not helping a tortoise on it's back. Then, he asks for the replicant, Leon, to describe his mother in several positive words. Leon responds by shooting Holden, who is still able to pull out his gun partly.
In a deleted scene of the movie, Holden talks to Deckard in the hospital after surviving Leon shooting him twice. He told Deckard that the Nexus's may be immune to the Voight-Kompff Test, and that the Replicants are so amazingly human.