In 1946 six Alcatraz prisoners attempted to escape by taking nine prison guards hostage and releasing the other prisoners from their cells. The six conspirators had planned to use their hostages to get across the prison yard, into the prison ferry, and across the bay. Their plan was foiled when they could not find the right key for the door to the prison yard. Time ran out and they missed the ferry launch. The plot quickly unraveled as prison officers and Marines descended on the island. After two days of bloody battle order was restored, but not before three of the escapees and two guards were killed.