The family of a custodial death victim at the Sungai Besar police station in Selangor last month is urging for the case to be investigated as murder.

The deceased, Mohd Nahar Kamsah, 49, was arrested for alleged drug offences on the evening of Oct 26 and was pronounced dead in the wee hours of the following day.

His mother Saliah Samad today demanded answers on the circumstances that led to her son's death.

"He (Nahar) was unwell and constantly vomiting prior to being arrested by the police at home.

"They arrested him, and we heard no updates of his whereabouts until the next morning," the septuagenarian told Malaysiakini.

The family only found out about Nahar's passing after being informed by police officers from the Sungai Besar police station at about 6.50am on Oct 27.

A post-mortem was conducted at the Sungai Buloh Hospital but the result is inconclusive, as it is listed as "pending laboratory investigations".

However, relatives who attended to the deceased's body for the final rites have claimed seeing bruises and injuries on Nahar's body.

They lodged a police report on Oct 31, urging for Nahar’s death to be investigated as murder.

The police previously said there were no criminal injuries detected in Nahar's death.

Bukit Aman Integrity and Compliance Department (JIPS) director Azri Ahmad said the deceased was found lying down and unconscious in the lock-up and a medical team was immediately contacted for further treatment. However, Nahar was pronounced dead by the attending assistant medical officer.

Azri said the Crime and Deaths in Custody Investigation Unit of JIPS would continue the investigation from various angles before handing over the results of the investigation to the coroner.

As for Saliah, she said her family just wants answers.

"We want a sensible answer about what exactly transpired. Just give us the truth, we don't want this to drag on any more," said the distraught mother.