SPECIAL REPORT: Child welfare workers search millions of homes a year without warrants. A mom who resisted paid a price.

Child welfare workers inspect the homes of 3.5 million children a year — and they almost never get warrants, an NBC News and ProPublica investigation found. In New York City, a mother is suing the caseworkers who took her two young sons, saying they violated her Fourth Amendment rights. (The city denies this, and the case is ongoing.)