Police believe up to four people may have been involved in an altercation that left a man dead in Darwin's northern suburbs on Tuesday night.
One person is in custody and police are calling for any witnesses to come forward.
They say the man was found unconscious when police were called to the Rapid Creek market precinct on Trower Road in Milner.
The man, believed to be in his 40s, was declared dead at the scene by paramedics.
At a press conference on Wednesday, Detective Senior Sergeant Jon Beer said the death was being treated as suspicious.
Detectives and mounted patrols remained at the scene throughout the morning.
"We have a person in custody at the moment in relation to this incident who we intend on speaking to later today, and I believe he will be able to assist us with our inquiries," Senior Sergeant Beer said.
He said police are investigating reports of an altercation occurring in the area before the man was found.
"We believe there was a group involved, we think up to three or four people involved in the incident," he said.
The victim is yet to be identified.
Shop owner Paolo Mu said he had provided police with CCTV footage.
He said while there was often public drinking and anti-social behaviour in the area, he was shaken to think a fatal altercation may have occurred.
"We've been here 40 years, we can deal with [anti-social behaviour]," he said.
"But seeing someone get killed is another thing."
Police are appealing for any witnesses who were in the area between 8 and 9pm last night to contact them.
