The Polit Bureau of the Communist Party of India (Marxist) on Thursday called for an investigation into the suspicious circumstances surrounding the death of Brijgopal Harkishan Loya, a 48-year-old Central Bureau of Investigation judge who died in 2014 when he was hearing the matter related to the allegedly staged encounter killing of Sohrabuddin Sheikh.

Bharatiya Janata Party National President Amit Shah was one of the suspects in the case. He was later acquitted by the judge who took over the case after Loya’s death.

“Disturbing questions of murder, bribery, subversion of law and the manipulation of institutions of our parliamentary democracy at the highest level have arisen, which must be seriously investigated,” the CPI(M) said.

Loya’s family has raised questions about a number of suspicious details regarding his death. Although official reports at the time called Loya’s death an otherwise unremarkable heart attack, members of his family said there are inconsistencies in many parts of this story, from the recorded time of death and the condition his body was found in to the way it was handled.

He took over as the judge in the Special CBI Court in Mumbai after another judge was transferred. At the time of his death in 2014, the only case he was hearing was that of Sohrabuddin Sheikh’s alleged encounter. Sheikh, a wanted criminal, was allegedly killed in a staged encounter by Gujarat’s Anti-Terrorism Squad. The original inquiry into the matter was accused of taking place at the behest of the BJP chief, who was then the home minister of Gujarat.