Four UK soldiers accused of forcing an Iraqi teenager into a river to his death had earlier attacked his fellow looters, a court has heard.
The four men deny the manslaughter of Mr Kareem
Aiad Salim Hanon, one of four Iraqis stopped by the soldiers in May 2003, told a court martial in Colchester, Essex, he was punched repeatedly.
Mr Hanon said they were then forced into the Shatt al-Basra canal, where Ahmed Jabber Kareem, 15, drowned.
Three Irish Guards and one former Coldstream Guard deny manslaughter.
Speaking later in Wednesday's proceedings, defence counsel for one of the men - L/Cpl James Cook, 22, of the Irish Guards - questioned Mr Hanon's motivation for complaining about the alleged incident.
Richard Lissack QC also pointed to what he said were inconsistencies in Mr Hanon's witness statements.
Mr Hanon, 25, a welder from Basra, and three other Iraqis were allegedly trying to steal from a garage on 8 May 2003 when they were caught by Iraqi police and the British soldiers.
After swearing an oath of allegiance on the Koran and speaking through an interpreter, Mr Hanon was asked what happened when he was stopped by the soldiers.
"First when he caught me, he hit me on the eye and then he hit me on the arm," he told the seven-strong military panel.
When asked who he was referring to, he replied: "The British soldiers involved."
He said he was physically assaulted by the four soldiers and, after falling on the floor, was dragged along the ground, injuring his arm and knee.
The men were repeatedly assaulted before being driven in a British armoured vehicle to the edge of the canal, Mr Hanon said.
On the journey, there was "continuous beating, kicking and hitting", he added.
Once at the canal, they were forced at gunpoint to enter the muddy, tidal waters of the canal, Mr Hanon said.
"They told us, 'Come on, swim', and they cocked their weapons and asked us to go to the river."
While two of the alleged looters swam to safety, Mr Hanon and Mr Kareem remained in the water.
When asked if Mr Kareem seemed able to swim, Mr Hanon replied: "No, once we were in the river he raised his hands and then went under the water.
"He then raised his hands again and then he vanished."
Mr Hanon said that when Mr Kareem went under the water, one of the soldiers had tried to help but was pulled back by his colleagues.
"One of the soldiers took off his clothes, he wanted to jump into the water, but the others did not let him," Mr Hanon told the panel.
"I saw him with my own eyes taking off his clothes. I saw him wanting to jump but the others stopped him and pushed him towards the armoured vehicle."
Mr Hanon said the soldiers then fled the scene and that Mr Kareem did not emerge.
On the opening day of the court martial, on Tuesday, the court heard that Mr Kareem's body was found almost two days after the alleged incident at the canal, which would have been at least 2m (6ft) deep, with a current and an uneven floor.
On Wednesday afternoon, Mr Lissack, for L/Cpl Cook, asked Mr Hanon: "What did you hope to achieve by the complaint?
He replied: "I was told that I would get compensation for the beatings and the injuries."
Mr Lissack also questioned whether the witness had even been there at the time of the alleged incident, after identifying eight instances where he said Mr Hanon's numerous statements were inconsistent.
Also standing trial are Sgt Carle Selman, 39, then of the Coldstream Guards and now serving with the Scots Guards, and Guardsman Joseph McCleary, 24, and Guardsman Martin McGing, 22, both of the Irish Guards.
The hearing has been adjourned until Thursday.