More than a decade before he turned a Midtown NYC office building into a killing ground, Shane Tamura stood out as a rising star on a high school gridiron. Police believe the 27-year-old shooter’s obsession with CTE,

Shane Tamura — who fatally shot four people at a Midtown East office building — said in a suicide note he believed he suffered from CTE and requested his brain be studied.

Four people were fatally shot during the horrific incident in Manhattan before the shooter turned on gun on himself.