The violent murder and dumping of a man's body in a river 20 years ago was a "crime of passion" committed by a jealous man who was having an affair with the victim's wife, police say.
Gofal Baziad, 52, is alleged to have stabbed Jason Palmer to death in 2004 to pursue a relationship with his wife.
Mr Palmer's body was found in a river at Menangle, south of Sydney, on February 29, 2004, three weeks after he was reported missing.
The 34-year-old's corpse was weighed down with rocks in the Nepean River but an initial investigation did not identify a suspect.
"We believe it was a pure crime of passion," Detective Superintendent Daniel Doherty told media on Tuesday.
Baziad was charged with the murder after 20 years of investigations by police who patiently put the missing pieces together, alleging the killer was jealous and obsessed with the UK expat.
"We will allege this fact is what led him to commit what we will say was a very violent crime," Det Supt Doherty said.
A 2007 coronial inquest found Mr Palmer was stabbed to death in the western Sydney suburb of Lakemba but the investigations stalled until being restarted in 2022.
Police then used information from telecommunications, movements and witnesses to charge Baziad, who was always a person of interest.
"Sometimes it just takes time to get the information you need," Det Supt Doherty said.
"It's like finding a key to a door, going into a room, finding further evidence and then finding another door."
Police are still urging anyone with information to come forward, as they suspect more than one person was involved.
After Mr Palmer's death, his wife continued the relationship with Baziad for several years and they lived together in Indonesia and Queensland before separating.
Baziad returned from Queensland two decades after the alleged crime to pursue labouring work in the same south Sydney region where Mr Palmer was killed.
On Monday he was surprised by detectives who arrested and charged him with murder.
On the other side of the world, Mr Palmer's family in the UK were contacted with the news they never expected to get, finally bringing closure.
"There are always mixed emotions making those kind of calls," Det Supt Doherty said.
"Mr Palmer from all accounts, was was loving man, he was a husband, he was a father."
Baziad faced court in Campbelltown on Tuesday where the matter was adjourned.
He is expected to appear at Burwood court on August 14.
