Shooting
Authorities in Madison said they are looking into the 15-year-old assailant's online activity, as well as a purported manifesto and potential bullying.
The suspect appears to have several social media accounts that could shed light on his motives.
An image showing the man's grinning face was captured when a hostel worker asked to see his smile, law enforcement sources told the news media.
Health insurance executive Brian Thompson was gunned down outside a New York hotel Wednesday.
WHAT'S HAPPENING
Brian Thompson dumped more than $15 million in stock before a federal antitrust investigation into the insurance giant was publicly revealed, a lawsuit claims.
The shooting happened as the historically Black university's 100th Homecoming Week was winding down.
Newly released CCTV and body camera footage shows the chaotic confrontation unfolding on a subway platform.
Police say that a man suspected of not paying the subway fare did not follow instructions and threatened officers with a knife.
State lawmakers from Laurel County urged residents in the area to stay home as police continued to search for the shooter.
Authorities say Vicente Joseph Arroyo killed miniature horses, goats, rabbits, guinea pigs, chickens, ducks and other types of birds.