She raised the question on Wednesday amid the criticism of some observations in the Supreme Court verdict on the 16th constitutional amendment.
"Now I see many writ petitions, suo moto rules. Was the High Court's conscience confined when such a big crime (Bangabandhu murder) took place?" she asked at a programme on Wednesday to mark National Mourning Day.
Bangladesh observes Aug 15 as the Mourning Day to commemorate Bangabandhu and most other members of his family, who were killed on that day in 1975.
The government of Khandaker Mushtaque Ahmed that took over immediately after the killings blocked the way for trial of the self-proclaimed killers by passing the Indemnity Ordinance.
Military ruler Ziaur Rahman legalised the ordinance through the Fifth Amendment to the Constitution in 1979. He also awarded jobs to 12 of the disgruntled army officers at Bangladesh missions abroad.
Hasina, the eldest daughter of Bangabandhu, asked why there had been no significant protest against the ordinance in those 21 years.
"There were so many big lawyers and people with conscience, but they did not protest that much," she said.
"A few intellectuals might have protested. No one else asked why the killers were given jobs abroad."
The prime minister said even Poland refused one of the killers as Bangladesh ambassador.
She said the subsequent governments after the killing of Bangabandhu made the state power a 'thing to feed their personal desires'.