Keller (Fallout: New Vegas)

Keller is an NCR Ranger working as an undercover agent investigating a chem ring in Westside

Background
This undercover agent of the NCR police spearheads an investigation with Lt. Boyd into chems trafficking in the outer Vegas area. Keller, an NCR Ranger, for months, has been operating from the pawn shop in Westside, gathering evidence to break up the drug ring. He recently arrested a chem dealer named Price for supplying chem ingredients to the local gangs, such as the Fiends and Scorpions.

With the dealer behind bars and awaiting questioning, Keller meanwhile poses as an associate of Price, handling his deliveries while he is away, covering up his absence as a recent business opportunity that Price went to check out. In turn, the agent intercepts incoming packages for Price to be used as evidence in his trial and to expose more of his associates. One of the people that Price made deals with to transport chem ingredients, the Camp McCarran quartermaster Daniel Contreras, is held under suspicion by Keller for his involvement in trafficking.

Contreras soon sends one of his associates, the Courier, to deliver a package of medical supplies to Price, unaware that his contact has already been apprehended and locked up.

Quests
Dealing with Contreras: The Courier is sent to Miguel's Pawn Shop to find Price, Contreras' contact, but instead Keller is there. Talk to him and report back to Contreras. He'll ask the Courier to kill Keller, but they can convince Contreras to work with him, Barter check of 70 or Speech check of 80. Whichever option is chosen, return to Keller and either kill him or convince him to work with Contreras.

Appearances
Keller appears only in Fallout: New Vegas.

Bugs

 * After talking with Keller, the dialogue option to pass a 7 INT/PER check pops up and does not work and always results in failure, despite having 7 Perception and 7 Intelligence.
 * Killing Keller with a silenced weapon after passing two of the Speech checks will circumvent the bug in Dealing with Contreras where the player does not receive This Machine and the final piece of dialogue does not trigger. This has to be done prior to returning to Contreras to report that Keller has been dealt with.
 * After talking with Keller and passing the INT/PER check, if one chooses to attack and kill Keller after he says the player is under arrest, upon returning to Contreras, the result and dialogue option will be the same as if you kept Keller alive and bribed him. If the player kills Keller in this order, they will not take a hit to their reputation with the NCR, and will gain access to the stash and This Machine. Although it disables the ability to turn him into Lt. Boyd (This occurs as of patch #2).
 * Sometimes, even if killing him without NCR reputation loss, the NCR will be hostile. A fix for this is to reload to the save after killing him but before the NCR went hostile and travel to the New Vegas Strip.
 * If the player says that they will rat out Contreras, and then kills Keller, no reputation will be lost with the NCR.
 * Upon passing the Speech check to convince Keller the player is merely seeking Price to purchase from him, they will gain no XP for doing so, unlike every other Speech check in the game.