The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) joined Rohnert Park fire officials this week in investigating the fire at Beverly Apartments that left 15 people homeless.
The cause of Monday’s fire is still undetermined, but investigators say they know it started in the carport and consider it suspicious.
On Thursday, investigators collected samples from the scene, which they will send to a lab for analysis. The process is expected to take several weeks.
“The bigger the fire, the harder it is to determine the cause of it because things burn up,” said Lt. John Marty, with the Rohnert Park Department Public Safety.
The fire erupted at approximately 1:25 a.m. Monday. Witnesses saw smoke coming from the carport, with flames quickly reaching the second story of the building on Beverly Drive, according to authorities.
Flames damaged seven apartment units, with four of the apartments being a total loss. One family had to jump out their second story window to escape.
The fire also destroyed five vehicles and damaged two others.
The insurance company for Beverly Apartments has also brought in its own fire investigators to assess the scene. Anyone who witnessed Monday's fire and has any information about what may have caused it is asked to contact Officer Jon Kempf at 707-588-3533.