Thu, Apr 12, 2012 3:07 PM EDT

Two people were killed on Sunday night by "an unknown number of subjects in camouflage clothing armed with rifles" that ambushed a truck carrying undocumented immigrants near the U.S.- Mexico border, according to the Pima County sheriff's department. The shootings occurred in Eloy, Arizona in an area northwest of Tucson "that is commonly used for human smuggling," according to a [statement made available to the press by the Pima County Sheriff's office. ](http://www.pimasheriff.org/bulletins/deadly-shooting-in-eagle-ranch-near...) Authorities identified one of the victims as Gerardo Perez-Ruiz, 39, of Toluca, Mexico, and the second victim was believed to be from Guatemala. "We're looking at the motives and who the suspects could have been," Pima County Sheriff's Deputy Dawn Barkman told [UPI.com](http://www.upi.com/Top_News/US/2012/04/12/2-illegal-immigrants-fatally-s...). "We're not going to speculate on any reasons for this crime at this time."