Later, John joined the American Indian Movement (AIM) and became its president from 1973 to 1979. He participated in the 1973 armed clash against police forces in Wounded Knee. Then, six years later, on February 11, 1979, John went to Washington, D.C. to protest the government's injustice toward Native Americans. John traveled to FBI headquarters with a group of AIM members where he burned the American flag on the steps in front of the building. Twelve hours later, John's pregnant wife, three children and mother-in-law died in their house which allegedly caught fire accidentally. John thought this was the FBI's way of trying to silence him. After this incident, John withdrew from the AIM group and began to take an interest in the artist.