A 37-year-old Portsmouth man was arrested following a suspected arson attack at a building containing a child care business.
The man was quizzed on suspicion of arson after metal cutlery was put into a microwave in a kitchen at the York Avenue building in East Cowes on the Isle of Wight.
The building also houses East Cowes library.
No-one was hurt in the attack between 1pm and 2pm on May 9.
Now police are appealing for more witnesses to come forward.
The man arrested was later released on bail pending further enquiries.
Call the Isle of Wight CID at Newport Police Station on 101.