“Washington Army National Guard officials are considering a request to use their helicopters to check sites found in a global positioning system device owned by serial killer Robert L. Yates Jr.Detectives are trying to figure out the significance of 72 locations that Yates, a graduate of Oak Harbor High School, had recorded in a hand-held GPS receiver.All but two of the sites are in Washington state, authorities said this week. One is in northern Idaho and one is in Oregon, near Portland.Most of the sites logged into Yates’ GPS device appear to be related to the confessed killer’s job as a helicopter pilot for the Washington Army National Guard, authorities said.But other sites interest Spokane’s Serial Killer Task Force, whose detectives still haven’t found the handgun tied to 10 women Yates admitted killing in Spokane County.Yates also confessed to killing a woman in Skagit County and a man and woman near Walla Walla.In October, Yates was sentenced to 408 years in prison after confessing to the 13 murders. He is now in jail in Tacoma, awaiting trial for two murders in Pierce County.The task force wants to find the weapon Yates used, as well as other evidence. It doesn’t have the money to hire a helicopter to fly to the sites, but still must check each location, sheriff’s Sgt. Cal Walker said Monday.’We need to see what Yates saw when he made those entries, said Walker, who supervises the five-member task force.Other police agencies, including those in Western Washington, are helping check the locations, Walker said.The task force asked the state Army National Guard for help, but state military officials said their resources couldn’t be used unless there was a drug connection, Walker said.Walker said he then attempted to persuade state guard officials that most of Yates’ victims are believed to have been tied to drug use or trafficking.Guard officials are now reportedly reconsidering the request. The computerized GPS receiver was found in a search of Yates’ home after his arrest April 18.The portable devices are used by pilots, backpackers, anthropologists and others interested in determining precise locations. The devices use satellites to detect longitude and latitude, and log entries can then be used to revisit a site.The GPS found in Yates’ home was turned over to specialists working for the Spokane County Information Systems Department. The department provides technical expertise to manage networks and computer systems.John Bottelli, an information specialist with the department, said he developed a computer-generated map plotting the 72 locations on Yates’ GPS device.It contains 20 sites in Western Washington and two on mountain passes in the Cascades. There are 48 sites in Eastern Washington, plus the single sites in Oregon and northern Idaho.A fairly significant number of the points are within the boundaries of either Fort Lewis or the Yakima Firing Center, Bottelli said.Walker said analyzing the locations wasn’t a high priority immediately after Yates’ arrest because detectives were processing DNA evidence and other investigative work linking him to specific murders. “