The fourth and final mob incident, and one of the most serious, occurred on May Day 1919. Several hundred demobilized soldiers, many of whom were in uniform, attacked a series of Socialist Party and Industrial Workers of the World headquarters buildings in New York City, including among their targets the Rand School. Doors to the building were locked against them, but raiders ascended the fire escapes outside and entered the 2nd floor Rand School library through the windows. Those who had gained entrance were dissuaded from violence by those inside the building and they peacefully exited without further incident.