Officials have named 63-year-old Anthony Quinn Warner as the man behind the mysterious explosion in which he was killed, but the motive has remained elusive.

Authorities haven't made any arrests and haven't released a motive for a shooting at an illegal marijuana growing operation that left seven people dead.

Police are searching a home on Milwaukee's north side as they hunt for clues about why an employee at one of the nation's largest breweries gunned down five co-workers before killing himself.

A Southern California high school is reopening for the first time since a 16-year-old student fatally shot two other students, wounded three others and killed himself last month.

Authorities say a Los Angeles County sheriff's deputy who said he was shot in a station parking lot was lying.

Police say a suspect is still on the loose after a business owner and three employees were killed inside a North Dakota business. 

The FBI has concluded its investigation into the deadliest mass shooting in modern U.S. history without determining a motive.  

South Lake Tahoe Police say they have arrested a man on a murder charge after he killed his roommate with a piece of split firewood at her home.  

Among the evidence recovered from the home of a man who shot and killed a rookie California police officer were two unregistered guns and a letter claiming police had been bombarding him with ultrasonic waves.