Amherst – Two fires that took place within an hour of one another on Saturday night are believed to be arson.

The larger fire left residents of a 21-unit Crestview Apartment complex on North Pleasant temporarily homeless Saturday night.

According to several media sources, Fire Chief Keith E. Hoyle of the Amherst Fire Department said Sunday that no one was injured in the 10:22 p.m. fire, although fire officials estimated that the building sustained over $35,000 worth of damage from intense heat and smoke.

Hoyle said over 40 firefighters, four pumper trucks, an aerial truck and three chief officers from Belchertown and Northampton responded to the smoky fire, which was located and contained in the basement, but left the building uninhabitable. According to state and local fire investigators, there was evidence of arson in a storage area in the basement.

Firefighters had to break through several walls on the first floor in order to control the minor fire. All other apartments in the complex had loss of electricity, smoke and water damage. The building is owned by Jones Properties of Amherst.

The smaller fire took place in a bathroom in 32 Alpine Commons around 9:30 p.m. on Saturday. There were no injuries, but the fire caused over $1,000 in damage. The building is owned by Aspen Chase Management.

The fires are additions to a series of fires that are believed to be arson in the Amherst area within the last month. In September, a fire was set in a basement storage bin the Presidential Complex apartment buildings on North Pleasant Street.

Local apartment owners are being advised by the fire department to keep storage areas locked and check smoke detectors.

The state fire marshal is investigating four different fires that took place in Sunderland over the last month, two of which were in apartment buildings.