No trace of drugs was found in the dope tests of two arrested suspects in connection with the killing of four members of a family in Rangpur city.

Rangpur Metropolitan Police Deputy Commissioner and Detective Branch (DB) chief Sanatan Chakraborty confirmed the development to journalists this afternoon after receiving the medical reports.

The suspects are Siddhartha Das, 19, and Mugdha Das, 23. Police collected their urine samples for dope tests at Rangpur Central Jail yesterday, citing security reasons. A team of DB police went to the jail around 1:15pm to collect the samples.

Mohammad Ashraf, a technologist at Rangpur Medical College, said the samples were collected yesterday noon and sent to a laboratory for examination.

The laboratory test results, along with the doctor's opinion, were sent to the DB police this noon.

“The doctor has given an opinion that no trace of drugs was found in their bodies,” Sanatan Chakraborty told journalists.

“We cannot say at this moment which direction the case will take,” he added.

Meanwhile, when asked how long traces of drugs remain in a user's body after consumption, Rashedul Haque Rahel, head of biochemistry at Rangpur Medical College, told The Daily Star, "Generally, for regular or long-term drug users, the presence of drugs can be detected if their urine is tested within a maximum of five to seven days after consumption. After this period, the chances of detecting drugs through a dope test decrease significantly."

He also added, "For irregular or occasional users, traces of drugs remain in the urine for a maximum of two to four days.

In this particular case, the urine samples of Siddhartha and Mugdho were collected yesterday after eight days of the detention. 

The bodies of former Rangpur Zilla School teacher Ganapati Chakraborty, 65, his wife Pritilata Chakraborty, 50, their daughter Agami Chakraborty Prarthi, 25, and son Priyam Chakraborty, 12, were recovered from their house and rooftop in the Daspara (Machhuapara) area of Rangpur city around 11:00pm on August 22.

Siddhartha and Mugdha, who are from the same area, were arrested early on August 23 in connection with the killings.

Our Lalmonirhat and Bogura correspondents contributed to this report.