An 8-year-old Alexandria boy drowned yesterday when he fell through the ice covering an outdoor swimming pool in a town house development in the Arlandria area.

Alexandria police indentified the victim as John D. Brock, of 2916 Landover St., the son of Hilda Brock, of that address.

Police said the boy apparently had climbed over a chain link fence to enter the pool area with a companion.

The other boy tried to pull the victim to safety, but was unsuccessful, police said. They said the Brock boy apparently was beneath the ice for 15 or 20 minutes before his body was recovered.

After being pulled from the water he was taken to Alexandria Hospital where he was pronounced dead.

Neighbors in the area described the pool as of Olympic size, with depths as great as 12 feet in one section. Water is usually left in the pool during the winter months, they said.

The pool had once been privately owned, but had recently been acquired by the City of Alexandria, according to the neighbors.

Police said the Brock boy apparently went onto the ice about 5 p.m. to play with a board lying there.

The second boy was reported under treatment last night for exposure.