Mexico City police have launched a massive manhunt for the mother-in-law wanted for the cold-blooded caught-on-video “execution” of a stunning former beauty queen. The suspected killer, identified as Erika Maria “N” in news reports, went on the lam shortly after the April 15 shooting death of Carolina Flores Gomez, a 27-year-old former Miss Teen Universe, reportedly because she was jealous of the victim’s hold on her son, Mexico’s El Universal reported . The chilling video inside Gomez’s posh