A foul smell from a locked room in Ashulia led neighbours to a grim discovery early Saturday: the decomposed bodies of a couple and a foetus.

The victims were identified as Alamgir Hossain, 42, and his wife, Nazma Akter, 33, both from Nawabganj upazila of Dinajpur. The five-month-old foetus was found beside them in their rented room in Madhya Jamgora.

Police suspect they were murdered, as a piece of cloth was found wrapped around Alamgir’s neck. The precise circumstances of the deaths, however, remain a mystery.

“We are yet to get any breakthrough… We’re analysing the victims’ call records and questioning the last person who called the couple to trace the motive,” Mohammad Tariqul Islam, officer-in-charge of Ashulia Police Station, told The Daily Star yesterday.

The Ashulia deaths are the latest in a disturbing series of incidents in which multiple members of the same family have been killed.

An analysis of recent media reports found at least 19 such incidents, leaving around 50 people dead. In at least 12 cases, two members of the same family were killed.

Meanwhile, 2,076 murder cases were filed in the first seven months of this year.

Motives in some cases included family disputes, conflicts over land or other property, financial disagreements, drug addiction, unemployment, and revenge. In others, they remain unknown or contested.

One of the most chilling incidents occurred in Rangpur’s Machhuapara last month, where retired schoolteacher Ganapati Chakraborty, 65, his wife Pritilata Chakraborty, 50, their daughter Agami Chakraborty, 25, and son Ayush Chakraborty, 12, were found dead inside their home.

Police arrested Mugdha Das, 23, and Siddharth Das, 19, in connection with the murders and said all four victims had been strangled.

Rangpur Metropolitan Police initially claimed the family was killed after Ganapati prevented the suspects from taking yaba on the roof of his house. Questions, however, arose over whether this fully explained the killings.

The case was subsequently transferred to the Detective Branch.

“We are working to identify the motive by analysing the statements of the two arrestees. We are also scrutinising the evidence found so far,” said Tofayel Ahmed, deputy commissioner (crime and operations) of Rangpur Metropolitan Police and media spokesperson for the case.

A similarly brutal attack took place in Lakshmipur’s Raipur upazila on June 25, when Shahinur Begum, 40, and her daughters Saima Akter, 21, Ikra, 17, and Sipa, 10, were hacked to death inside their home.

Two died at the scene and the other two at the hospital.

Witnesses said a man carrying a machete entered the house around noon and attacked them. As he tried to flee, locals caught him and beat him to death.

“We failed to identify the motive since the lone attacker was killed,” Raipur Police Station OC Mohammad Nizamuddin Bhuyan told The Daily Star.

In Chattogram’s Anwara, Swapan Dash Gupta, 65, and his wife Kalpana Dash Gupta, 55, were allegedly killed by their only son on July 25.

Police and locals said their unemployed son, Rimon Dash Gupta, attacked them during an argument over his employment. He was also described as drug-dependent.

In another case, accounts of the motive differed.

Businessman Abdus Sattar, 90, his wife Suraiya Begum, 76, and their domestic worker, Tahmina, 20, were killed at a house in Sylhet city on August 12.

Police arrested Babul Mia, 40, and initially linked the killings to a dispute arising from an alleged relationship between him and Tahmina. The couple’s relatives rejected that explanation, while their daughter alleged in the case statement that a land dispute was behind the murders.

Other incidents included allegations against husbands over the killings of their wives and children, sons over the killings of parents and siblings, and a father over the deaths of his two children.

On May 8, a man was named the principal accused in a case over the deaths of his wife, their three children, and his brother-in-law in Gazipur’s Kapasia.

Tawohidul Haque, associate professor at Dhaka University’s Institute of Social Welfare and Research, said the incidents had different immediate causes but shared deeper social and structural failings.

Speaking to this correspondent, he said, “Family disputes, property, influence and the tendency to take revenge are factors. Failure to investigate crimes and conclude trials quickly is also a reason behind such violence.

“The state must create conditions in which people feel secure within their families, neighbourhoods and wider society.”

Questions also remain over whether perpetrators are being brought to justice.

A Police Bureau of Investigation study examined 238 murder cases decided in 2015 and 2016. All defendants were acquitted in 123 cases, or nearly 52 percent, while convictions were secured in 115. The cases had been filed between 1986 and 2015.

The PBI identified delays in investigations, weaknesses in evidence collection, loss of witness interest during lengthy trials, and difficulties preserving reliable testimony as factors affecting convictions.

Asked yesterday about the recent killings of multiple members of the same families, Mostofa Kamal, additional inspector general of police and chief of the PBI, told The Daily Star, “We cannot just say that families are being targeted based on three or four incidents.”

Asked about the 19 such incidents reported over the last six months, he said the PBI would look into them if the cases were transferred to the agency.

(Our Noakhali, Lalmonirhat and Savar correspondents contributed to the report.)