Upon striking, the miners and their families had been evicted from their company-owned houses and had set up a tent colony on public property. The massacre occurred in a carefully planned attack on the tent colony by Colorado militiamen, coal company guards, and thugs hired as private detectives and strike breakers. They shot and burned to death 18 striking miners and their families and one company man. Four women and 11 small children died holding each other under burning tents. Later investigations revealed that kerosine had intentionally been poured on the tents to set them ablaze. The miners had dug foxholes in the tents so the women and children could avoid the bullets that randomly were shot through the tent colony by company thugs. The women and children were found huddled together at the bottoms of their tents.

The Baldwin Felts Detective Agency had been brought in to suppress the Colorado miners. They brought with them an armored car mounted with a machine gun—the Death Special— that roamed the area spraying bullets. The day of the massacre, the miners were celebrating Greek Easter. At 10:00 AM the militia ringed the camp and began firing into the tents upon a signal from the commander, Lt. Karl E. Lindenfelter. Not one of the perpetrators of the slaughter were ever punished, but scores of miners and their leaders were arrested and black-balled from the coal industry

“On April 18,” said Mr. Walsh, “five days before the Ludlow horror, you got a letter from Mr. Bowers personally addressed to John D. Rockefeller, Jr., in which he stated: ‘Another favorable feature of the strike situation is the organization of a military company of 100 volunteers at Trinidad next week; they are to be armed by the State and drilled by military officers. Another squad has been organized at Walsenberg; they are independent of the militiamen and will be subject to orders of the Sheriff of the county. These volunteers will draw no pay from the State.’ Didn’t you get from this letter the knowledge that that was a volunteer company that the Colorado Fuel and Iron Company was to pay?”

“If that is what the letter states I must have understood it so,” answered Mr. Rockefeller.

“I will ask you if, immediately after the Ludlow massacre, on the next day, you did not receive this telegram from Mr. Bowers: 'Following withdrawal of troops by order of Governor, an unprovoked attack upon small force of militia yesterday by 200 strikers forced fight, resulting in probable loss of ten or fifteen strikers. Only one militiaman killed. Ludlow tent colony of strikers totally destroyed by burning 200 tents, caused by explosion, showing ammunition and dynamite stored in them. Expect further fighting today. Militia to be reinforced. Suggest you give this information to friendly papers. L. M. Bowers; What friendly papers?”