Who is Alwyn Cashe and why did Alejandro Villanueva choose to honor him?

Part of the name “Alwyn Cashe” can be seen on the helmet of Steelers left tackle Alejandro Villanueva, during the Sept. 14 game against the New York Giants.

The Steelers team stands behind Alejandro Villanueva in the tunnel during the National Anthem before the Bears Sunday, Sept. 24, 2017 at Soldier Field in Chicago Il.