A Canberra man accused of trying to break into a sex offender's home told police he had gone to "educate" the man, not threaten him, a jury heard on Wednesday.
Prosecutors allege that Paul Arthur Palmer, 39, Daniel James Nicholas, 32, and Joshua Darcy Watson, 33, went to the sex offender's townhouse one morning and tried to force entry.
They say the men were armed with a knife and went to the home with the intent of causing the man harm, or at least threatening him.
All three have pleaded not guilty to one count of attempted aggravated burglary.
Police arrested the three men after seeing them allegedly flee from the sex offender's home early in the morning of February 20.
A video recording of Mr Palmer's interview with police was played to an ACT Supreme Court jury on Wednesday.
In it, Mr Palmer is dressed in a white forensic suit, and he tells the officers he had on his phone a video the sex offender had filmed of himself abusing an underage girl.
In the police interview, Mr Palmer said someone had contacted him about the video and to tell him "this was going on".
He said the girl should be in school. He said that though police had the video days ago the man was still contacting the girl.
He said there was more than one girl.
Mr Palmer said he went to the house to bang on the door, show the sex offender the video through the window, and warn him someone "undesirable" like him knew about what he was doing.
"Just tell him, you ring this girl again, I'll be back," he told police.
He denied his intention was to scare the man, and he denied he had tried to get inside the house.
An officer asked if he wanted to threaten man, to which Mr Palmer said: "Not threaten him, educate him."
He told police it "pisses me off" that detectives had the video five days ago, but the man was still free.
He denied he intended to get inside the house, saying he'd had a sledgehammer in his car if that was his intention.
A police officer also gave evidence on Wednesday, telling the trial police found a knife and a piece of wire on the concrete outside the man's house.
Police arrested the sex offender shortly after the February 20 incident.
He has since pleaded guilty to four counts of rape and one indecent act committed against four girls aged between 14 and 15.
He will be sentenced next year.
The trial continues.