CROOKS IN AMBUSH IT was gala night in the city of Westford. Streets were strung with brilliant lines of colored electric lights. Store fronts were illuminated, throwing their brightness upon festooned posts and displaying the elaborate decorations of their own windows. Tourists, driving through the main streets, gained the impressions that this city of two hundred thousand was engaged in celebration. As the boosters phrased it, Westford was a "live town" that was definitely "on the map"; the city attracted visitors from every town within a hundred miles. Business was booming in Westford; it was predicted that good times