My uncle residing forcefully in my house

My father had bought land in Muzaffarpur in 1998 on his own money as my grandfather died in 1988. He took home loan for building house and still paying EMI of loan. My uncle (father's own younger brother) lives in this house on my father's permission since 2007. Now we have to built another storey and asked my uncle to vacate the house. But he refused to do so and gave death threats to my family if we forced him to vacate. Can we vacate house legally and if yes then how??