Gunmen stopped a pickup truck full of illegal immigrants, shot some and took the rest captive in an attack that killed at least three people and wounded two, authorities said. Authorities were trying to determine who the gunmen were and said some of the immigrants remained missing. Investigators believe at least two the immigrants attacked Thursday were Guatemalan. The men shot shot two men and a 15-year-old girl fatally along a known smuggling corridor near Tucson, and wounded another man and a woman. The gunmen then forced several others in the group of nine or 10 immigrants to leave with them, Pima County sheriff's officials said. The bodies of one man and the girl were found in the rear seat of the pickup truck that had been carrying the group. The crime was similar to a robbery Wednesday night more than 70 miles (115 kilometers) south, near the Mexican border, said Rick Kastigar, the Pima County sheriff's criminal investigations chief. In that incident, four men carrying assault weapons and wearing ski masks robbed 18 immigrants, but no one was reported injured.