FOXBOROUGH — Selectmen promised Tuesday to deliver answers about how a longtime former teacher, Boy Scout leader, and swim coach allegedly was able to prey on boys decades ago without being stopped or exposed.

The vow came as a 51-year-old man who identified himself as a victim of William E. Sheehan begged the board to stay firm in selectmen Chairman James DeVellis’s recent pledge to “turn over every stone and file cabinet” until someone is held responsible.