A fire Tuesday night at a Knights of Columbus building in Fair Lawn is being investigated as arson, officials said.

Authorities said it’s suspected that a Molotov cocktail was throw into the building, causing the fire.

The incident happened 10:30 p.m. Tuesday at 1616 Maple Ave. Officials said a neighbor across the street noticed a suspicious man standing outside the building and hollered at him, sending the man running.

A milk jug filled with an accelerant was also found outside the building, police said.

"It kind of breaks your heart to see something get damaged that you put a lot of time and effort into it, and it's more of a community building than the Knights of Columbus because everybody uses it. It hurts the community,” Grand Knight Michael Chiocchi said.

Chiocchi said the building is insured, and firefighters were able to contain the flames to the office space and bar. The bequest area was untouched.

"It'll be useable as soon as we get some electric and maybe some smoke damage out," Chiocchi said.

Officials said no security cameras are installed at the Knights’ building, but they will be checking camera at neighboring establishments.