Police have apprehended the wife of Cradle Fund Sdn Bhd CEO Nazrin Hassan to facilitate a probe into his murder.

Selangor police said they had also arrested the 43-year-old woman's ex-husband, also 43, to shed more light on the June 14 incident in which Nazrin was found dead after a fire engulfed his room in his Petaling Jaya residence.

Initially investigated as sudden death, the case was reclassified as murder by police last month after they received post-mortem reports as well as the full reports from the Fire and Rescue Department.

Selangor police CID chief Fadzil Ahmat said the male suspect was arrested in Sepang at 1 am today.

Subsequently, investigators picked up the victim's wife about an hour later at a house in Taman Tun Dr Ismail, Kuala Lumpur.

Fadzil said police have obtained a seven-day remand order against the two from the Petaling Jaya Magistrate's Court.

Meanwhile, a source familiar with the investigation revealed that the mobile phone explosion, which was initially claimed to have started the fire that killed Nazrin, never happened. 

The wounds on the deceased's body were also not consistent with shrapnel from an explosion, he said.

"There were traces of petrol on his body ... and there were wounds on his head."

Authorities had earlier denied claims by Nazrin's family members that the latter had died from injuries caused by a phone that had exploded while being charged near his bed. 

Selangor Fire Department director Azmi Osman had clarified that forensic investigators had not reached any such conclusions and pointed out that it was Nazrin's family which had made the claims. 

According to reports, Nazrin's brother-in-law had posted on social media that one of the two mobile phones Nazrin was using, had exploded. 

"If you remember, the day Nazrin died, shortly afterwards there was a viral message which linked the death to the explosion of a mobile phone. Who wrote the viral message? Such an incident never happened ... and the telco could sue the related party," said another source.

The source added that for the last several weeks, investigators had been working hard to link a person who is believed to have played a role in the murder, based on all the evidence gathered.

"The clues pointed to someone ... but the investigators need strong evidence to charge the person in court," he said, adding that someone close to Nazrin had been infuriated when the report revealed that Nazrin did not die from injuries caused by the mobile phone explosion. 

Last month, Nazrin's wife had released a statement saying that she and her family were being kept in the dark over the progress of the investigation and that the fire department had refused to give her a copy of its investigation report.