PORTLAND, Ore. (KOIN) — A small bus went up in flames and caught a nearby commercial building on fire in Northeast Portland early Wednesday morning, fire officials said.

Around 1:18 a.m., Portland Fire and Rescue received a report of a fire on NE 102nd Avenue and NE Wygant Street. Fire officials said the fire spread to part of the building’s roof, but crews had both the bus and building fires controlled in about 15 minutes.

PF&R said no one was hurt, and an investigation is underway to determine what caused the fire.

This comes as fire crews are investigating a series of fires in the same area from earlier in the week. PF&R said two vacant houses and a vacant warehouse caught fire on Monday night.

PF&R told KOIN 6 News it’s too early for fire investigators to know if all four fires are related, but “it is definitely something they are looking into as part of their investigation.”