Vandals broke into a Brentwood mosque and left hate-ridden messages on the walls and doors, officials said yesterday. The Shah-e-Najaf Islamic Center of Suffolk County’s president discovered the writings at around 9 a.m. when he returned to the mosque after several weeks in Pakistan, said Syed Naqvi, the head of the mosque. On one wall, the burglars wrote “white power” and drew a large swastika using a black marker.