The fire service in the Cook Islands says two recent fires at a residential home and a commercial property were both deliberately lit.
Two weeks ago a home in Titikaveka was completely gutted and two weeks earlier, the Turoa Bakery and adjoining Saltwater Cafe were destroyed by fire.
Investigators also concluded that two separate school fires last month were the result of arson.
The Fire Chief, Nga Jessie, says investigators concluded the blaze at the bakery and cafe was purposely lit, as the owners saw two bikes speed off from the rear of the property.
He says there is reason to believe the house fire was also lit by an arsonist.
"The two occupying the house said that they heard the cracking and woke up and then saw the veranda part burning. Because there's no such thing below it like rubbish or any kind of fuel like petrol that would've started the fire, they were convinced that somebody lit something and put it underneath the deck."
Nga Jessie says investigators believe there is a chance the arsons are all linked.