A massive fire at a Minneapolis lumberyard over the weekend is being called arson after surveillance video captured two trespassers on the property right before the blaze broke out.

At a news conference Wednesday, arson investigator Sgt. Sean McKenna said surveillance video from Shaw Stewart Lumber Company shows two trespassers crawl under a gate at the lumberyard, then one enters a building only to run from it minutes later as smoke pours out of the structure, KARE 11 says.

Dozens of firefighters battled the blaze, which started Saturday night. Smoke from the fire could be seen from nearby Interstate 35W.

Part of the one-story warehouse collapsed, but firefighters were able to save other buildings on the property.

Anyone with information is asked to call the city's arson hotline at 612-673-3070 or 800-723-2020, FOX 9 reports, or click here for more on reporting suspected arson.