Police are searching for a man as they investigate the death of another man from multiple stab wounds to his neck in what is believed to be a drug deal gone wrong.

The body was found inside a home on Kembla St, Croydon Park in southwest Sydney about 5pm on Monday.

It was initially reported the victim, who has not yet been formally identified, was aged in his 50s, however police now believe he was a 29-year-old Malaysian national.

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A 32-year-old man was arrested at the home and taken for assessment at hospital, where he remains under police guard.

NSW Police are now appealing for help finding a second man who they believe can help with the investigation.

The man, described as being Asian in appearance, was last seen on Kembla St, Croydon Park on Monday.

He is described as having a solid build and was wearing a black jumper with red symbols on the back, blue jeans, black shoes, a black hat and carrying a black satchel.

Forensics officers were seen at the home on Tuesday, with the property heavily taped off.

Evidence markers have been placed in the driveway.

Superintendent Christine McDonald described the incident as a gruesome crime, adding the victim’s injuries were horrific.

It is still unclear who lives at the property.

McDonald said the stabbing is not believed to be domestic-related or gang-related, with police treating the incident as a drug deal gone wrong.

Anyone with any information about the second man, or about the incident, has been urged to contact Crime Stoppers.