A cluster of fires that broke out along a trail on the eastern side of Mill Mountain on Sunday evening has raised firefighters' suspicions.

"When you have five fires in five different areas with no ignition point, it's a pretty good indication, it's almost a surefire bet" of arson, said Dave Hoback, Roanoke Fire/EMS chief.

Hoback said the fires were along a trail 300 to 400 yards down the mountain from the Mill Mountain Star, between the Star and Fishburn Parkway.

He said no structures were endangered, and that between three and four acres were burned in total.

He said crews would remain on the mountain through the night, monitoring the fire sites.

"Being at night, it's pretty difficult to tell," exactly what happened, Hoback said. An investigation is ongoing.

Walnut Avenue and Fishburn Parkway were closed late into Sunday night, but firefighters expected they would reopen before morning.

--Jessica Marcy