After six months of having soldiers deployed to the southern part of the state and with tensions easing due to the pacifying influence of union leader Louis Tikas and the National Guard–and despite a murder in Forbes in March 1914 that saw the Guard burn a striker tent colony down–the vast majority of the troops are withdrawn back towards garrisons in Denver in mid-April 1914 to reduce cost. Ludlow Massacre On 20 April 1914, 177 remaining Colorado National Guard troops and militia engaged in a shootout at the Ludlow tent colony, resulting in what is known as the Ludlow Massacre. Major Patrick Hamrock and Linderfelt organized the battle against the strikers, which killed around twenty on the UMWA side, including at least eleven women and children who died in a fire started by the soldiers and a boy struck by a machine gun bullet. Louis Tikas was also killed, with Linderfelt later being found responsible for his murder but was not convicted or punished by a military trial. A single National Guard soldier was killed by gunfire from the strikers. During the following week, strikers sought revenge against the mining companies and National Guard, launching dozens of deadly attacks across the state in what became known as the 10-Day War. General Chase immediately moved hundreds of troops back south to pacify the strikers. Captain Hildreth Frost led a small group of National Guard troops on 28 April in the northernmost battle at a mine in Louisville. The same day, a National Guard medic was killed and several wounded in a firefight for the hogback near Walsenburg. The fighting ceased on 29 April after President Woodrow Wilson ordered the federal-level Army to disarm the strikers and turn-back the National Guard. The strike concluded without much further violence in December 1914. First World War and interwar period In June 1916, prior to the United States' involvement in the First World War, the Colorado National Guard was deployed to the Mexican–American border to support General Pershing's expedition against the Mexican revolutionary Pancho Villa. The deployed troops returned in February 1917. After the National Guard was activated in 1917 to deploy to Europe to participate in the First World War, the Colorado State Defense Force was activated for the first time to take over the responsibilities of the departing Guard. Called to federal service on 5 August 1917, the 1st Infantry Battalion was redesignated