A 20-month-old boy drowned in a bathtub when his mother went to answer the front door, police said.

Debbie McClure, 31, was running water for the bath for the toddler, Willie Vaughn III, and his 3-year-old sister when the doorbell rang about 7:45 p.m. Tuesday, said Police Lt. Clark Combe."She ran to answer the door and was there about three minutes when the sister ran out and said, `Willie is laying face-down in the tub,' " Combe said.