Accused killer felt 'stupid' dumping body

A man accused of murdering his Thai national drug dealer in southwest Sydney felt like a stupid person for dumping the body, a jury has been told.

Alex Dion admits he disposed of his ice dealer's body and clothes after he was killed in his Belmore apartment but denies it was by him.

"I'm embarrassed in myself how stupid ... take the body and dump it ... make me feel like a stupid person I done what I done," Dion told the NSW Supreme Court on Tuesday.

The 40-year-old has been extradited back to Australia where he has pleaded not guilty to murdering Wachira "Mario" Phetmang between the evening of May 25 and May 27 in 2018.

Mr Phetmang's extensively decomposed body was found by a truck driver bound and gagged in bushland outside Sydney Olympic Park on June 6.

An autopsy later found the cause of death was likely from at least 27 head injuries causing fractures to his skull, while death by asphyxiation from being gagged was also a possibility.

Two days later Dion flew to America with Mr Phetmang's possessions including a mobile phone and credit cards he used when possible.

He denies the crime had anything to do with why he left, saying he was worried about his wife's health.

The US citizen has accused his former flatmate Adib El-Anani of the murder and said he did him a "big favour" by disposing of the body in his car which he then thoroughly cleaned inside.

"He's the one who killed Mario and I am the one who take the body and I am the one who put it in my car and I am the one who dumped the body," Dion said.

Dion wrote in a text message to Mr El-Anani: "What did Mario do wrong? Was his only crime that he is gay or a drug dealer?"

Mr El-Anani had frequently stopped responding to Dion's text messages which caused further friction in their deteriorating friendship, the court heard earlier.

Before Dion's extradition, he called Crime Stoppers in Australia on numerous occasions saying he had information that detectives could use to "catch the killer".

A senior constable, who accompanied Dion as he flew back to face trial, recalled a conversation in which Dion said Mr El-Anani had been waiting for him at their apartment with two men in gloves who forced him to take Mr Phetmang's body away.

But Dion does not remember this conversation.

The trial continues.