Oregon Public Broadcasting

National Guard helicopters and searchers on horses have joined about 500 volunteers looking for Kyron Horman.

Missing Portland second-grader Kyron Horman

The seven-year-old disappeared seven days ago and authorities still don't know whether he wandered away from school or was taken.

The search area has been expanded to two miles around Skyline Elementary.

Sean Richards is with a team from Klamath County. It's relieving other crews.

Sean Richards: 'It's an honor for us to be here to back them up. We've got new boots to put on the ground and hopefully we'll bring him home."

The teams are checking everywhere from back roads, to powerline clearings. Some areas are being searched for a second time.

About 18 counties from around the state are now helping. The search crews are housed at the Wapato Jail site.