December 25
A dynamite bomb destroyed a portion of the Llewellyn Ironworks in Los Angeles, where a bitter strike was in progress - 1910
And this: December 25, 1910 -
http://www.workdayminnesota.org/index.php?history_9_12_25_2010, where a bitter strike was in progress. In April 1911, James McNamara and his brother, John McNamara, secretary-treasurer of the International Association of Bridge and Structural Iron Workers, were charged with the two crimes. James McNamara pleaded guilty to murder and John McNamara pleaded guilty to conspiracy. James McNamara was sentenced to life in prison at San Quentin; he died there in 1941.
Labor history found here:
http://www.unionist.com/today-in-labor-history & here:
http://www.workdayminnesota.org/index.php?history_9_12_25_2010