The 27-year-old man who shot and killed four people at a Midtown office building on Monday carried a note in his pocket, police sources told ABC News.

The mayor of New York says Shane Devon Tamura may have been targeting the headquarters of the NFL when he opened fire at a skyscraper in midtown Manhattan. A three page suicide note found in Tamura’s wallet and reviewed by NBC News contains several references to the degenerative brain disease CTE,