Police are looking for up to 10 men after a 24-year-old man was stabbed to death in a Western Sydney park overnight.
They allege a fight broke out between two groups, believed to be known to each other, at Leonard Reserve in Roselands just before 10pm.
Paramedics treated the man at the scene but he was unable to be revived.
New South Wales Police Superintendent Sheridan Waldau said officers were now searching for up to 10 men seen running from the park, leaving a blood trail on the ground.
"We do not believe it's a random attack," she said.
"We believe these two groups may have been known to each other."
Blood spots were seen on the ground near the attack, and visibly distressed family members attended the scene shortly after, Superintendent Waldau said.
"We do have a number of people that we spoke to, but we're not getting a great deal of assistance," she said.
"We have a 24-year-old young man who is deceased, and we are asking anyone with information to come forward," she said.
"We need to know why this happened."
She said the victim was not "adversely known" to police and there was no evidence the attack was gang or organised crime related.
