Medford police believe a homemade firebomb ignited the Sunday arson fire that burned about 25 acres of grass and brush in southeast Medford, closing Interstate 5 for several hours.
Medford police Lt. Tim Doney said this morning that fire inspectors found the device in brush off the Bear Creek Greenway where the 2:50 p.m. fire ignited and eventually jumped the freeway.
"It wasn't fireworks jury-rigged," Doney told the Mail Tribune. "It was something homemade and designed to start a fire."
The device was found about 1,000 yards south of the San George Estates Mobile Home Park on East South Stage Road, Doney said.
Medford fire inspectors and detectives are asking for help in identifying the person or people responsible for the blaze.
Anyone with information about the fire, or about suspicious people or activity in the area Sunday, is urged to call investigators at 774-2230.