The Qadianies and Ahmadis where declared non Muslim due to

  1. Non believing of finality of prophethood
  2. Believing of Mirza Gulam Ahamdies teaching
  3. Believing of continuing prophethood
  4. None of these

Ahamdies  not believe  on finality of  Prophethood .

It was declared in 2nd amendment in 1973 constitution.