Richard Pérez-Peña

Kik goes further than most widely used apps in shielding its users, making it hard to know who is using it — or how.

A day after a leader of the armed occupation of a federal wildlife refuge was killed and eight other anti-government activists were arrested, law enforcement officials called on those who remained at the refuge to go home, saying they had only themselves to blame for what had happened.

Michigan’s attorney general opened an investigation Friday into lead contamination in Flint’s drinking water, and the governor asked President Barack Obama to declare a disaster as National Guard troops fanned out across this anxious city to help distribute bottled water, water filters and testing kits.

On campuses, deciding how to respond to threats of violence often falls to administrators, who have a small window in which to act and little verified information.

A Virginia school district closed its schools amid an angry backlash, including a possible “risk of harm to school officials,” over an assignment that asked high school students to copy a Muslim creed in Arabic calligraphy.

On the day she and her husband killed 14 people and wounded 21 others, a woman pledged allegiance to the Islamic State in a Facebook post, officials said, as the FBI announced that it was treating the massacre as an act of terrorism.

San Bernardino police spent the night combing the scene of a shooting rampage that left 14 dead and 17 others wounded and examining the backgrounds of two suspects, a husband and wife who died in a shootout, looking for reasons behind the attack.

A heavily armed couple terrorized a California city, killing at least 14 before leading police on a manhunt culminating in a shootout that left the suspects dead.

Mayor Rahm Emanuel ousted Chicago’s police superintendent Tuesday, after the city’s police department came under fire over an officer shooting a teenager 16 times, and for resisting, for more than a year, to release a video of the fatal shooting.

The Environmental Protection Agency, which accidentally spilled 3 million gallons of toxic wastewater from an abandoned mine in Colorado, lacks the technical skills to handle such tricky projects, a government assessment reported.

Videos involving white officers and black civilians have become ingrained in the nation’s consciousness -- to many people, as evidence of bad police conduct. And while they represent just a tiny fraction of police behavior, they have begun to alter public views of police use of force and race relations, experts and police officials say.

The Arkansas Legislature on Tuesday passed its version of a bill described by proponents as a religious freedom law, even as Indiana’s political leaders struggled to gain control over a growing backlash that has led to calls to boycott the state.

The police conducted a manhunt in this tense and battered city on Thursday in search of whoever shot two officers as they worked at a protest after the resignation of the chief.