LAWRENCE, Mass. - Police say a dog searching for a gun in a snowbank accidentally pulled the trigger with its paw, firing the weapon.
 
No humans --or dogs -- were hurt.
 
The episode started at about 2 a.m. Sunday when an officer on patrol heard three gunshots. When the officer went to investigate, he saw a vehicle speed away.
 
When the car pulled over, police saw a man leap out and bury something in the snow.
 
Ivan, a dog handled by the Essex County Sheriff's Department, was called to the scene to find whatever was buried in the snow. Police say he started digging furiously and fired the gun.
 
Three men were arrested and police determined the gun had been stolen in Manchester, N.H., in October.