We followed the supply chain for batteries used in millions of U.S. cars to villages in Nigeria where people are being poisoned by lead. Peter S. Goodman, who covers economics and geopolitics for The Times, describes our yearlong investigation.

The variety of federal forces deployed to support President Trump’s mass deportation campaign and anticrime efforts continues to expand. Often, it can be difficult for the public to tell them apart, or to understand what powers each agency has.