(CNN) -- A day after launching their search, authorities found bodies Friday that appear to be that of a woman and her despondent ex-boyfriend inside the man's truck in central Arizona.
The 1999 Ford F150 truck, belonging to 47-year-old Tom Watson, was located around 10 a.m. by Yavapai County Sheriff's Office deputies near Horsethief Basin, just outside Crown King and about 80 miles north of Phoenix, Goodyear, Arizona police spokesman Ralph McLaughlin told CNN.
Two dead bodies were inside the vehicle, which authorities preliminarily identified as those of Watson and Tara Shermerhorn, his 31-year-old former girlfriend, according to McLaughlin. No information was immediately available about how they died or the condition of their bodies.
Goodyear police first began looking for Watson around 5 a.m. Thursday, after receiving a missing-persons call. He had left a note with instructions on how to get rid of his property and indicating that he was despondent, the city's police department said earlier in a statement. According to CNN affiliate KTVK, his message read, in part, "This is it."
Early in their search for him, police "pinged" Watson's phone and determined that he was near highway I-17 traveling north of Phoenix. At some point, police said his phone shut off.
Shermerhorn was last seen at her work at 9 p.m. Wednesday, the Goodyear police said. The following afternoon, her family members called police concerned that she might be missing. Their worries were piqued when Shermerhorn failed to pick up her niece after school, KTVK reported.
Police said they believe that, after work, Shermerhorn drove to her house -- where her vehicle remained, even after she was reported missing.
Her phone was tracked to near Crown King in Yavapai County later Thursday, with Goodyear police saying they believed the phone, at least, was then stationary.
That information helped authorities concentrate their search, which led to their discovery of Watson's dark blue Ford truck, which sported a South Dakota license plate.
The Yavapai County Sheriff's Office is partnering with the Goodyear Police Department in investigating the case, including working to backtrack the locations of Watson and Shermerhorn over the past several days, McLaughlin said.