A cabdriver and his passenger who witnessed a purse snatching assault Sunday, chased after the assailant, caught him and held him until officers arrived.

A 70-year-old woman was knocked to the ground after the assailant spun her around and tore the purse from her arm.Salt Lake police said the attack occurred at 10 p.m. at 1400 W. North Temple after the man confronted the woman on the street.