DENVER --A sting of fires in Capitol Hill has neighbors concerned about a possible arsonist.
The latest incidents include two fires started early Friday in the area around 13th Avenue and Ogden Street.
Over the last couple of weeks, residents say there have been several dumpsters and mattresses set on fire.
Flames from a dumpster fire early Friday jumped up the side of an old apartment building. It caused major damage to a first floor hallway and an upper unit that was vacant.
Four people were temporarily evacuated from their apartments. The cause of the fire, which broke out about 3:30 a.m., is not known but fire officials are looking at all possibilities, including fireworks.
Residents say fireworks are a nightly events in some of the alleys, and they're concerned. They say this is the seventh fire in the area in about two weeks.
"Our place got hit in front. I know a car up the street has been hit," says Graham Blandy who called 911 Friday.
He doesn't think the fires are accidents. "Arson I'd say because it's happening repeatedly and it's happening between 12 and 3 o'clock at night."
Some bushes in front of a nearby building also burned early Friday. FOX31 Denver found evidence of spent fireworks next to the torched dumpster.
"Sparks can easily turn into large fires and possibly it's what we saw last night," says Denver Fire Department Mark Watson. "We had several calls in that area of bushes on fire, fireworks in the area."
Meredith Neiss is one of many neighbors who are nervous. "Between the Denver weather being so dry and how old these buildings are I feel like they're kind of tinder boxes as it is, so it's very concerning."
Some who live in the area say they've requested -- and police have agreed -- to step up late night patrols.
"Anytime between 12 and 3 you know Friday nights, weekends, it's happening and it's freaky," Blandy says. "I don't want anybody to get hurt."