We have also obtained documentation that shows a Victoria Police officer has shredded evidence submitted for a court matter.
This is unacceptable criminal behaviour from the personnel of Victoria Police, no doubt below 'community expectations'.
At the start of the video, Mr Mareangareu tells Mr Foster, aged 16 at the time, not to be smart. As the teenager spells his name, the policeman asks: "One name? Is that one name?"
Moments later, someone says "smartarse" and Mr Mareangareu throws a punch at the boy.
Prosecutors told the court the punch left the teen with a badly bloodied nose.
Later in the footage another policeman, Dennis Gundrill, tells Mr Laird: "Get rid of that video right now." Mr Laird stops the recording but starts a new recording soon after.
The court heard that Mr Laird's father later paid a "significant sum of money" to experts in retrieving lost data and the videos were recovered.
In the second recording one teenager calls out: "You can't twist my arm. Ow! Get off my arm please."
On this video, one of the policemen says they want to speak to the teenagers about burglaries.
Prosecutors allege Mr Mareangareu unlawfully assaulted Mr Foster and that after the boys were arrested, both officers deleted the recordings from Mr Laird's phone and lied in police statements.
Mr Mareangareu has pleaded not guilty to intentionally causing injury, false imprisonment, two charges of attempting to pervert the course of justice, and three of perjury.
Mr Gundrill has pleaded not guilty to false imprisonment, perjury and two charges of attempting to pervert the course of justice.
Outlining his case on Thursday, prosecutor Bruce Walmsley, QC, said the teenagers were on their way home from a friend's house, where they had used marijuana and Mr Foster drank two beers. They told the policemen they hadn't done anything wrong.
After the scuffle, the boys were arrested and separately taken to a police station and charged with assaulting police, resisting police and possessing marijuana, which had been found in a backpack.
Mr Walmsley said as Mr Laird left the police station he discovered the recordings on his phone had been deleted. "He will tell you he didn't delete them," the prosecutor told the jury.
Prosecutors allege the policemen didn't tell their supervising officer about the videos or that they allegedly deleted them.
Mr Walmsley said Mr Mareangareu and Mr Gundrill adopted an attitude of "let's get rid of the video, let's get it to court and then we will all be free".
Mr Mareangareu compiled a brief of evidence against the boys, the court heard, and in May 2015 encouraged Mr Foster's mother to get her son to go to court and do a deal with a prosecutor.
The trial will continue on Friday when the accused men's lawyers address the jury.