Rage (1972)

In Wyoming, sheep rancher Dan Logan and his teenage son Chris camp out on their land. Their sheep are grazing about while the sheep dog is guarding them. An Army helicopter is seen buzzing around but shortly disappears. Dan sleeps in his tent while Chris sleeps under the stars. In the morning, Dan finds Chris convulsing, unresponsive and bleeding from the nose while his sheep are dead. Dan races to the hospital where the doctors isolate his son and test Dan for signs of illness. A young Army doctor, Major Holliford, working at the hospital as a specialist in biochemical sciences, asks Dan about Chris's symptoms. He suggests that it could be insecticide poisoning. Dan remains in the hospital as a preliminary precaution but the hospital refuses to release him or to allow him to see his son. After a week of lies and delaying tactics from the part of the hospital staff, Dan escapes and finds his son's dead body at the morgue. He vows to find out the truth and punish those responsible.