5:07pm: According to Mike DiGiovanna and Bill Shaikin of the L.A. Times, Adenhart and friends Courtney Stewart and Henry Pearson were killed. The fourth friend, Jon Wilhite, was taken to the hospital in critical condition.
3:12pm: Yahoo's Tim Brown and Kevin Kaduk have reactions to the Adenhart tragedy. Baseball America profiles his career, and also has a statement from Angels GM Tony Reagins. MLB.com's Lyle Spencer also has a nice tribute.
10:16am: Awful news today. TMZ reports that Angels pitcher Nick Adenhart was killed in a felony hit-and-run car accident early this morning. Two others (one affiliated with the Angels organization) were killed in the crash, and the offender was caught and hospitalized. The 22 year-old had just tossed six scoreless innings the night before, the best performance of his young career.
NBC Los Angeles and the L.A. Times have more on the story.