DALLAS, Ore. (KOIN) — A house fire led to an investigation that reportedly revealed an illegal indoor marijuana grow operation over the weekend, according to the Polk County Sheriff’s Office.

The sheriff’s office said in a Facebook post the fire happened shortly after 4 a.m. on Sunday on Oakdale Road in Dallas. The post said upon their arrival, deputies found the home “completely engulfed by flames,” but all residents had safely evacuated.

While on the scene, deputies and firefighters say they observed indications that the location was the site of an indoor marijuana grow operation, which was later confirmed by detectives through additional investigation.

During the execution of a search warrant, 399 marijuana plants and approximately 100 pounds of processed marijuana was located, according to law enforcement.

PCSO said 50-year-old Jinyou Pan was arrested in charged with unlawful manufacture, possession and delivery of marijuana.