Indian Administrative Service (IAS) officer D.K Ravi's grandmother passed away due to a heart attack on Friday.
Ravi, who was posted as Joint Commissioner in Commercial Tax Department, was found hanging from a ceiling fan in his apartment earlier on Monday.
His mysterious death led to an outcry for a CBI probe with legislators of the opposition parties taking the appeal to Karnataka Governor Vajubhai Rudabhai Vala.
Family members of the bureaucrat had staged a sit-in protest earlier on Wednesday, demanding a CBI probe into the incident after their meeting with Chief Minister Siddaramaiah.
Several organisations, including the ABVP, are staging protests and criticizing the state government for not handing over the case to the CBI.
The state government has ordered a probe by the Criminal Investigation Department (CID) in the case.
The CID, which is collecting statements from the people who interacted with Ravi during the time preceding his death, is expected to submit its interim report in a couple of days.
Whistle blower Ganesh Kondaliya had earlier on Tuesday said that the deceased officer was planning raids on big developers to unearth commercial tax evasion and had discussed about the real estate developers with the latter over phone on March 12.