Police have begun an arson investigation after two incendiary devices were thrown into a Kaimuki home early this morning.

Three people were home when the devices was thrown at a house at Claudine Street and 16th Avenue near Mau Umae Nature Park around 1:30 a.m. 

A dog and a neighbor were credited by police for alerting the occupants to a small fire that was started in a bedroom.

A second device was recovered from the roof of the house, said Fire Capt. Terry Seelig.

No one was injured. 

Police said the house at the time of the incident was occupied by a woman, 67; and two men, ages 70 and 38.

Police said the fire had been extinguished by the occupants before firefighters arrived.

Seelig said damage, confined to only one room, was estimated at $5,000. 

The device found on the roof did not start a fire, Seelig said.