The cause of death of deputy public prosecutor Anthony Kevin Morais has been called into question during the murder trial today.

Forensic medicine specialist Dr Ahmad Hafizam Hasmi, who performed the post-mortem examination, testified in the High Court in Kuala Lumpur that "probable asphyxiation" (suffocation) was the cause of the death.

However, lawyer N Sivananthan, who is representing one of the accused, doctor and army pathologist Colonel Dr K Kunaseegaran, raised concerns on the cause of death during his cross-examination of Hafizam.

Sivananthan said Kevin's younger brother, David Ramesh Morais, had testified that the cause of death was "unknown", as stated in the death certificate.

"David gave evidence under oath in court and in answering a question from the judge, said the death certificate was available and the cause of death was written as unknown," Sivananthan said during the ninth day of the Kevin Morais murder trial.

This is in contrast to the cause of death as stated in the post-mortem report and confirmed by Hafizam (photo) and his colleague Dr Nurliza Abdullah, which is "probable asphyxiation".

Hafizam said he was not aware of this and that he was not shown the death certificate.

So far, the death certificate has also not been provided to the defence counsel, Sivananthan added.

Hafizam also revealed that he was present during a meeting in November last year with the three brothers of the deceased, along with the investigating officers.

Two out of the three brothers had requested for a second post-mortem during this meeting, he said.

However, Hafizam reiterated that he had not seen Kevin's death certificate.

The court was also told that "probable asphyxiation" was not only stated as the cause of death in the post-mortem report but also on the National Registration Department form (JPN.LM02), which is to verify and issue death registration and burial permit.

The two documents were prepared at the same time, Hafizam said, and he had filled in the cause of death for the JPN.LM02 form and signed it for verification.

Upon further questioning by Sivananthan, he revealed that the officer in charge of the post-mortem also needs to submit a JPN.LM10 post-mortem form to verify the cause of death.

Sivananthan then questioned why this form had not been shown to Hafizam to identify during the trial proceedings.

"I suggest that this document shows a different cause of death," he said, to which Hafizam disagreed, adding that the original JPN.LM10 form is with him.

The defence counsel also questioned why the use of "probable asphyxiation" as opposed to "asphyxiation" (for the cause of death).

This is because the body was in a state of advanced decomposition so the pathologists could not find the usual markers for asphyxiation such as red dots in the eyes from burst capillaries and cyanosis in the palms of the hands, Hafizam explained.

"There is proof that asphyxiation happened based on findings obtained during the post-mortem and also lab investigations that took into account negative findings.

"The two of us (himself and Nurliza) are of the same opinion that the cause of death was probable asphyxiation," he clarified.

Six men – G Gunasekaran, 48, R Dinishwaran, 24, AK Thinesh Kumar, 23, M Vishwanath, 26, S Nimalan, 23, and S Ravi Chandaran, 45 – claimed trial to the charge of murdering Morais between 7am and 8pm on Sept 4, 2015, between Jalan Dutamas Raya Sentul and No 1, Jalan USJ1/6D, Subang Jaya.

The first accused, Col Dr R Kunaseegaran, 53, pleaded not guilty to abetting the six men in Kevin's murder at the same place, date and time.

The trial before Justice Azman Abdullah continues tomorrow.

Kevin was reported missing on Sept 4 last year.

He was last seen leaving his apartment at Menara Duta in Kuala Lumpur in a Proton Perdana car bearing registration number WA6264Q.

His remains were found in a cemented drum at Persiaran Subang Mewah, Subang Jaya, near Kuala Lumpur on Sept 16 last year.