A jury convicted Raymond Bellavance Jr. on Friday after deliberating for four hours.
Prosecutors said "anger and jealousy" caused Bellavance to set fire to the coffee shop, where his ex-girlfriend worked as a waitress. Deputy District Attorney Alan Kelley told jurors Bellavance was "a volatile man" who was quick to anger because his former girlfriend was having a relationship with the shop's owner, the Bangor Daily News reported.
The Grand View Coffee Shop in Vassalboro, a town of about 4,000 residents just north of the state capital, Augusta, burned down June 3, 2009.
The defense insisted Bellavance didn't do it.
Bellavance testified he wasn't jealous. He said other people, including a man who testified he helped set the fire, were lying.