A dozen men accused of murder produced knives and baseball bats then "set upon" a group of people resulting in a teenager's fatal stabbing, a jury has been told.
The defendants faced Brisbane Supreme Court on Wednesday for the third day of their trial after all pleaded not guilty to the murder of Girum Mekonnen.
Prosecutor Nathan Crane told the jury the 19-year-old died near the deck of a demountable building located across a creek from soccer playing fields at a park in the north Brisbane suburb of Zillmere on September 13, 2020.
"He suffered a wound to his abdomen that severed the most significant vein in the human body ... somebody had put a bladed weapon to the most vulnerable part of the body and pushed it in 25 centimetres," Mr Crane said.
All defendants also pleaded not guilty to 10 other charges of causing grievous bodily harm with intent, unlawful wounding with bats, knives and machetes, and assault causing bodily harm against 10 alleged victims.
Mr Crane said Mr Mekonnen had been part of a group of people drinking alcohol and playing cards at the park when the 12 accused formed a "cordon" around the deck where they were sitting.
"They arrived. They produced weapons. They immediately started using the weapons," he said.
The prosecution's case is that each of the defendants are liable for murder as they had a common criminal purpose in taking part in or encouraging the attack that killed Mr Mekonnen and injured 10 other people.
"The group was set upon in this park ... These are 12 men who acted in union. They were co-ordinated, they walked together. They were disguised by COVID masks, bandanas and hoods over their heads," Mr Crane said.
The defendants are Kresto Wal Wal, 28, Gabreal Wal Wal, 31, Santo Wal, 36, Yohana Wal Wal, 23, Joseph Lokolong, 28, Majok Riel Majok, 23, Alex Edward Deng, 22, Chan Kuchmol Kon, 28, Abraham Ajang Yaak, 30, Ben Abio, 23, Juma Makuol Deng Makuol, 27, and Malat Akoi Makuach, 25.
Mr Crane said DNA, fingerprint, CCTV, dashcam footage, text message and mobile phone location evidence would show the defendants gathered weapons and travelled from Ipswich, west of Brisbane, to park in Zillmere in a convoy of three vehicles.
The jurors were told they could find the motive for the attack was retaliation for the bashing of John Wal Wal at an Ipswich shopping centre five days before Mr Mekonnen was stabbed.
John Wal Wal is the brother of four of the defendants: Kresto, Gabreal and Yohana Wal Wal and Santo Wal.
Mr Crane told jurors they would hear from witnesses that Kresto Wal Wal was "front and centre" during the attack on Mr Mekonnen's group and they heard the defendants say "no way you are going to get away with this" and "this is for my brother".
The defence barristers for some of the defendants are due to give brief opening addresses on Thursday.
