Sagira Morshed Salam, a researcher at Bangladesh Institute of Development Studies, was shot dead in broad daylight on July 25, 1989 in the capital's Bailey Road area.
The investigation agencies could not solve the murder case in the last 30 years, as one order of the High Court restricted further investigation into the case.
That changed on June 26 this year, when a High Court bench of Justice M Enayetur Rahim and Justice Md Mostafizur Rahman lifted the stay order.
The High Court bench also ordered the Police Bureau of Investigation (PBI) to investigate the case further and directed the trial court to finish its proceedings.
The PBI could manage to solve the case within just five months after getting the High Court directive.
The Business Standard looks into the PBI's investigation process in this case.
Without any forensic investigation, and without any help of modern technology the PBI solved the case just by focusing on the small clues left from investigations conducted almost three decades earlier.
Talking to the Business Standard, Deputy Inspector General and PBI chief Banaj Kumar Majumdar said the trial proceedings and further investigation into the murder could not be conducted for the last 28 years because of the stay orders.
"The High Court issued the stay order after hearing a petition filed by one of the suspects, Maruf Reza, who challenged the trial court's directive for conducting further investigation into the case in 1991. We picked up our investigation from the point where it had been left at that time," said Banaj.
"We tried to investigate the person who filed the petition and how he benefited from it," he added.
In 1990, police submitted the charge sheet to the lower court concerned against one Minto alias Mantoo alias Mauron. On January 17, 1991, a Dhaka court framed charges against him.
The court also recorded statements of eight witnesses in the case.
The name of Maruf Reza, a relative of former home minister Mahmudul Hasan, came to light when the trial court was recording statements of the witnesses.
Then the lower court directed the police to further investigate the case on May 23, 1991. Later, Maruf Reza filed a revision petition with the High Court, challenging the lower court's order.
Following this, the High Court on July 2, 1991, stayed the trial proceedings of the case and further investigation into the murder.
Inspector Rafiqul Islam, the current investigation officer of the case also said Maruf Reza was detained by the Detective Branch of Dhaka Metropolitan Police at that time.
"Maruf Reza's name surfaced when the witnesses were giving statements. The Detective Branch detained him but released him later. There might have been some pressure to release him and submit a charge sheet mentioning the case as mugging," he said.
So, Maruf Reza's name was on the list of suspects from the very beginning of the PBI's investigation.
Banaj Kumar Majumdar also said they tried to reach every person who was possibly involved in or aware of this incident.
"At first, we contacted the plaintiff and the victim's husband Abdus Salam Chowdhury. After talking to him we came to know about the first eyewitness, a rickshaw-puller named Salam Molla," Banaj said.
The PBI also came to know about some domestic altercation in the family between Sagira and her in-laws.
"After trying for a few months, we were able to find out the rickshaw-puller," said the PBI chief.
Salam Molla, now 56, gave the first breakthrough in the PBI's investigation.
He told the PBI that before getting shot, Sagira identified one of the motorcycle riders, who shot her with a gun.
Salam Molla also told the PBI that addressing one of the assailants Sagira said, "Hey, I know you! Why are you here?"
That led the PBI to success. The PBI tried to find out the person whom Sagira recognised before getting killed.
The investigation officer also said the case had been treated as a mugging case before the PBI started the investigation.
"The rickshaw-puller told us that if it was just an incident of mugging, Sagira would not be able to identify the mugger. So, we focused on the family crisis and altercations between the three sisters-in-law," Inspector Rafiqul added.
"We also tried to know the details of the family crisis and got some important clues there," he said.
"Then we interrogated the suspects – Sagira's brother-in-law Dr Hasan Ali Chowdhury, his wife Sayedatul Mahmuda Chowdhury, her brother Anas Mahmud Rezwan, and Maruf Reza, one of the patients of Dr Hasan.
"At last, while we were interrogating the suspects one by one, we came to know that family altercations led to the murder. The doctor couple hired Maruf Reza in exchange of Tk25,000, and Anas Mahmud Rezwan also took part in the killing," Banaj Kumar Majumdar said.
The PBI chief also said they tried to collect information on the revolver and the motorcycle used in the killing. But they could not find any trace of those.
"Maruf Reza confessed before the court that he had collected the revolver from Harhar Munna, a criminal from the capital's Jatrabari area. We also tried to reach him, but unfortunately we came to know that he died during a gunfight two years ago," he added.
The PBI found no connection of Minto, who was mentioned in the charge sheet submitted by police in 1990, with the murder of Sagira.