KUALA LUMPUR, May 16 — The unusual case of an autistic man charged with murdering his Malaysia-born stepmother two years ago after she was reported missing is causing a stir in Australia, in a case that has stumped police investigators.

The absence of the victim’s body, however, has baffled police investigators and is hampering the prosecutors’ case as her death was never formally established.

Ah Bee Mack, 56, reported to be a native of Malaysia by The Syney Morning Herald (SMH) today, was reported missing by a relative in August 2010.

Her autistic Australian stepson, Brent Donald Mack, 26, one of three stepchildren with whom the widow had been living with after her husband died in a nursing home the same year, was charged on September 3, 2010 with Ah Bee’s murder.

He was also charged with fraudulently taking A$162,000 from his stepmother’s bank accounts, but prosecutors have withdrawn that charge for the time being.

The Supreme Court heard the case against Mack was “entirely circumstantial” because there was no body and none of the usual forensic data generally presented at trial, the daily reported.

Questioned over Ah Bee’s whereabouts, Brent initially told police she was alive and well, but refused to disclose her location.

He later said Ah Bee was overseas; however, passport records showed she has not left the country.

Brent also claimed she had run away with a new boyfriend and cut all ties with family.

Questions over Brent’s fitness have also been raised, with the case being heard all the way in the Western Australian Supreme Court last year.

The accused’s lawyer, Seamus Rafferty, had told the court Brent is not fit to stand trial because of his autism, adding that the latter did not have the mental capacity to enter a plea, let alone stand trial for murder, the paper reported.

But prosecutor Dave Dempster had described Brent as an “intelligent man who runs a computer repair business”, SMH reported.

Ultimately, Supreme Court Justice John McKechnie found Brent was fit to stand trial in a judge-only capacity via videolink, the Sydney-based daily reported.

The trial, which was to start yesterday, has been  adjourned to July 5 after it was revealed Brent is “assisting police” with their investigation, the paper reported.