Lately a number of questions came up in our playgroup regarding Andre LeRoux, so here's a short "Questions and Answers summary for this crypt card. Most of the information is taken from the VtES Usenet Newsgroup "rec.games.trading-cards.jyhad". The key for understanding most rulings is that Andre's special ability is used when the bleed is successful, which is the same time windows Spying Mission is played/used.
Question: If another vampire is bleeding for one, can I use Andre's special ability at all? In the end, if the bleed is reduced by one, the action was not successful in the first place.
Answer: Yes, you can. The bleed is considered successful, even though the bleed is later reduced to zero. But since the vampire didn't remove any pool during the action, the Edge is not awarded for the bleed action.
Question: Can Andre LeRoux use his ability more than once per action, for example twice, when the bleed by the other vampire is for two?
Answer: No, Andre can't. The special ability follows the "during X, do Y" template, which limits the use of the ability to once per bleed.
Question: Can Andre LeRoux use his special ability on himself, that is effectively bleeding for two?
Answer: Yes. There's no indication in his card text which limits the use of the ability to other vampires.
Question: Can I use Andre's special ability on a bleed for 4 of another vampire before the targeted player has an opportunity to play Archon Investigation?
Answer: No, you can't prevent the other player playing Archon Investigation. Archon Investigation is played when an attempt to bleed for four or more is made, and Andre's special can only be used when the bleed is successful (which is later in time, of course).
Question: If a vampire bleeds using Night Moves and increases the bleed for 1 (or more), and Andre uses his special ability to reduce the bleed by one, is the resulting bleed for zero or one?
Answer: The bleed is still for one. Night Moves does reduce the bleed per se, but limits the bleed to one.
Question: If Andre bleeds for three (e.g. by having his special ability earlier), can he use his special ability on himself to bleed for four while he's safe from the targeted player playing Archon Investigation?
Answer: Yes, he's save from the targeted player playing Archon Investigation, since when Andre is using his ability, the bleed is already successful and it's too late This is the same argument why you can't play Archon Investigation against a bleed which has been increased beyond three via Spying Mission.