Witness prevents purse snatching

A good Samaritan foiled a robbery in Kailua on Tuesday when he confronted a teenager trying to make off with a stolen purse, police said.

A woman, 55, had a purse on her lap at 8:22 p.m. when someone took it from her and ran, police said. A witness, 26, heard the screaming and began chasing the suspect, police said.

When the witness confronted the boy, he dropped the purse and ran, police said.

The boy was arrested a short time later, police said.