As an in-house counsel for the city of Newark, N.J., in the 1970s, Edward Petit-Clair defended police officers accused of civil-rights violations. Now he knows what it’s like to be a plaintiff.

On a wintry evening two years ago, Petit-Clair was about to take a shower in his home in an over-55 community in Brick Township, N.J., when officers with drawn guns barged in. They had seen suspicious signs that suggested a burglar who had been plundering homes in the neighborhood was inside the house.