A witness at the Bloody Sunday inquiry has told the hearings that he and his then teenage colleagues would frequently engage in rioting because that was their "idea of fun".
John Duffy, who was 14 at the time of the killings in 1972, also said he was praised by a teacher for letting off a canister of CS gas close to a British army barracks before the ill-fated march on that day.
Mr Duffy said he and his friends "used to riot all the time and throw stones at soldiers. That was our idea of fun".
He said on the day of the shootings, he and others went up to a barricade soldiers were erecting "to do a bit of heckling".
None of this was any different from their normal behaviour, he said.
After he let off the canister, one of his teachers came around the corner and asked who had thrown the gas canister, he said.
"I said it was me and he said 'good on you' and I was very proud of myself", Mr Duffy said.