Indonesian police have outlined what they believe happened on the night one Australian was shot and killed and another injured at a villa in Bali.

Zivan Radmanovic, a 32-year-old from Melbourne, was killed just after midnight on June 13 at a villa near Munggu Beach in Bali’s Badung district.

Another Australian, 34-year-old Sanar Ghanim, who is also from Melbourne, was beaten in the attack.

Police previously said that they had arrested three Australian men. At a news conference on Thursday, they gave new details of an investigation they said was supported by the Australian Federal Police.

Investigators say two Australians are suspected of arriving on a scooter and opening fire. Another Australian is accused of organising the crime.

Police have not revealed a motive in the killing. But they said they had enough evidence to bring the men to trial on charges of premeditated murder, which could carry a life sentence or the death penalty.

The crime scene investigation and surveillance cameras have showed that two suspects, identified by their initials as MC and PT, were the shooters, Bali Police Chief Daniel Adityajaya said in Badung.

The third suspect, identified as DJF, helped the others by buying a hammer used to break down the villa door, renting two cars and three motorcycles and buying ferry and bus tickets to flee the island, Adityajaya said.

One of the suspects was caught at Jakarta’s Soekarno Hatta international airport on June 16. The other two were arrested in Singapore and Cambodia the following day, with the help of Interpol, and returned to Indonesia.

On Thursday, police presented trio handcuffed and dressed in orange prison uniforms.

The three Australian suspects at Thursday’s press conference. Photo: AAP

Witnesses at the villa told investigators that two gunmen arrived on a scooter at the villa around midnight. Radmanovic was shot in a bathroom of his room, where police found 18 bullet casings and two intact bullets.

Radmanovic’s partner, Jazmyn Gourdeas, 30, told police that she woke to her husband’s screams. She cowered under a blanket as she heard multiple gunshots.

Gourdes later found her husband’s body and the injured Ghanim. His wife also testified to seeing the attackers. The women are sisters.

Adityajaya said police had retrieved one of two guns that were thrown away by the suspects near a rice field, about 700 metres from the villa.

They also found bullet residue and gloves and balaclavas inside a white van used by the three men. The same residue was also found on the bodies of two of the suspects.

Police did not detail how they believe the suspects obtained the weapons, which are heavily regulated in Indonesia. Adityajaya said police were still gathering evidence.

He said Ghanim and the two women had been moved to a secure location.