The January 20 ceremony, held three days after Georgi Kutoyan was found dead in an apartment in the capital, was attended by his former colleagues and ex-President Serzh Sarkisian.
The Investigative Committee has launched a criminal investigation into possible incitement to commit suicide, and spokeswoman Naira Harutiunian told RFE/RL that no suspects had been identified so far.
Harutiunian said the autopsy had not found trace of violence on Kutoyan’s body beside the gunshot wound.
A lawyer by education, Kutoyan was appointed HAAT chief in February 2016 after serving as an assistant to then-President Sarkisian.
Kutoyan was dismissed by Prime Minister Nikol Pashinian in May 2018 shortly after popular unrest forced Sarkisian to resign.
He kept a low profile while in office and did not make any public statements after his dismissal.
Kutoyan is the second former top security official to be found shot dead in the last four months. Hayk Harutiunian, a former head of the Armenian police, was found dead at his country house in September.
Harutiunian reportedly had a gunshot wound to the head, and investigators suggested he had committed suicide.
During the previous months, Harutiunian was interrogated several times in a criminal investigation into postelection violence in Yerevan in 2008.
Investigators said Kutoyan was not questioned as a suspect or a witness in that case.