(Capcom's primary storyline)
The Querétaro mansion incident (tentative) was a mass murder of a Mexican army squad by the black marketer Glenn Arias. It took place at a mansion in the Mexican state of Querétaro.
Chris Redfield and a unit from the Mexican army was sent to rescue Cathy White and her son at a mansion in Querétaro. The unit landed and traversed across a forest and found the mansion. The captain of the unit told his men to split up into teams of three and they entered the mansion and find the interior empty. They saw a set of stairs leading up to the mansion's rooms. As their operation began, the three teams went up the stairs and entered various rooms.
The captain's team arrived in the dining room, Chris' team arrived in a living room, and another team went into a bedroom. In the dining room, the Captain and his team did not see anything out of the ordinary, however, they did not notice that there was a zombie hiding in the fireplace. In the living room, Chris and his team did not find anything peculiar, however, they are startled by a grandfather clock. In the bedroom, one of the soldiers was suspicious of what was under the bed, upon lifting the blanket, the soldier was relieved as he only found a toy truck. Unexpectedly, the toy truck's wheels moved, catching the soldiers off guard, the soldiers then dismissed it. The wheels of the truck moved a.
Nonetheless, it was soon revealed that Zack was the one who was controlling the toy truck. He came out of his hiding place and soon and it was revealed that he has been infected with the "A" virus and attacked them. Chris and his team heard the other soldiers' screams and headed towards the bedroom only to find it empty. One of the soldiers saw the truck and attempted to inspect it, only to be pulled under the bed by a zombie and be devoured by a group of them. Chris quickly kills them off along with the zombified soldiers from the other team, he then encounters a zombified Zack. A brief struggle ensues and Chris threw a grenade into the bedroom to deal the zombies, he and another soldier exited the room to find cover.
The other soldier was bitten by Zack and he quickly succumbed to his wounds and became a zombie, Chris finished him off. Meanwhile, the captain attempted to contact the rest of the unit to no avail. A dismembered female zombie from the fireplace suddenly assaulted them, the captain and another soldier were taken down. Two other soldiers attempted to shoot the zombie and retreated into a hallway, only to be sliced into pieces by wire traps set up by Glenn. He exited the hall and smirked. Meanwhile, Chris was running from zombies, he killed a few and escaped through a window.
He encountered Glenn and had a long fight with him. In the end, he lost to Glenn. Glenn revealed that he turned Kathy into one of his 'products', a large mutant and mysterious woman appeared, the mutant released a zombified Kathy from a chain. She then shambled towards Chris as other zombies did the same as Glenn and his associates left. Reinforcements just arrived in time to save Chris, one of the soldiers shot the zombies with a barrage of bullets from a gatling gun and killed all of them. Chris, upset by these turn of events, held Kathy's dead body in his arms and screamed in rage.
The perpetrators were Glenn Arias, a black market arms dealer, and his associates Diego Gomez and his daughter Maria Gomez. The mansion was probably one of Arias' testing grounds and facilities where he kept his 'merchandise'.
Not much is known about the fate of the mansion after Chris is rescued. Though, one could assume that it would be destroyed by the explosions that came after.