March 12 fire at a Northeast Portland auto scrapyard that caused mandatory overnight evacuations in the Cully neighborhood was caused either on purpose or by discarded cigarettes, Portland Fire & Rescue officials say.

Investigators found evidence of homeless camps near the scrapyard NW Metals, but no evidence of camping on the property, given that there was no evidence of "candle use or warming fires."

One of the scrapyard owners, Moyata Anotta, had told KOIN-TV that the business had experienced problems with homeless people in the past.

Anotta had also said he suspected the blaze was intentional, according to a report by KATU-TV. Investigators didn't rule that out.

The cause of the fire officially remains undetermined, but investigators have have not ruled out two possible causes: discarded cigarettes or purposeful "ignition with an open flame."

"While smoking was not allowed on the yard, I did find two cigarette butts within the yard fencing near the entrance gate to the north," the investigator Nicole Brewer writes in the report, released today in response to a public records request by WW.

"While this was too far away to be the source of ignition for this fire, I could not exclude the possibility that someone could have smoked on the yard and discarded material that was ultimately consumed by the fire."

Fire officials say the cause of the fire is likely to remain officially undetermined.

"Based upon the information developed through the investigation, it is my conclusion that the fire originated in the 'fluff' pile under the shredder and, due to the inability to exclude discarded smoking material and incendiary causes, the cause of this fire is undetermined," she writes.