Haidar Khan was the leader of one of the Bakhtiari tribes in Iran in 1924 and a main character shown in the movie Grass.
Haidar Khan's 9 year old son, Lufti was interviewed by author Bahman Maghsoudlou in 1990 and authenticated the events depicted in the movie shot in 1924.
According to Lufti, Haidar Khan contracted yellow fever the following year and died as a result.[1]