Otago Explorer bus driver Ken Smeaton said he was in Stuart St and saw two people running towards the entrance gate of the church from the Harrop St side of the building about 3.50pm.
‘‘When I looked up I noticed the guy [St Paul's Cathedral verger Will Anglin] was on his hands and knees and yelling at these kids,'' Mr Smeaton said.
He leapt from his bus and confronted the teenagers, but the boy escaped and the girl verbally abused him and threatened to assault him, before she ran towards Hoyts cinema.
Mr Smeaton called 111 as the girl, who he understood was about 16 years old, ran down an alleyway. She returned to the Octagon a few minutes later and was apprehended by police, he said.
Mr Smeaton said he would confront anyone in the same situation again.
‘‘I would do it again, because I'm proud of this city and we don't need that sort of thing again,'' he said.
Sergeant Tania Baron, of Dunedin, said police understood Mr Anglin had tripped as he pursued the teens, but was not injured. Mr Anglin could not be contacted last night.
The three teens involved were well known to police. None was arrested, but, because they were aged under 17, they would be referred to the police youth aid section.
It was unclear last night if any charges would be laid.
Cathedral dean the Very Rev David Rice said last night the graffiti incident was the third he could remember in recent times.
‘‘We've had graffiti on doors; we've had it on the stonework; we've had it on the glass.''
Last year, Mr Rice, who is leaving Dunedin in May, went public with his concerns about vandalism and safety issues at the cathedral after security cameras were destroyed. That had led to the doors being shut to the public except when volunteer ‘‘guardians'' were on duty.
Dunedin City Council youth strategy chairman Cr Michael Guest last night described the graffiti as ‘‘mindless criminal behaviour''.
‘‘It is not freedom of expression. It's just plain old vandalism. I hope they are dealt with in court and have to pay an extra penalty,'' Cr Guest said.
During the first two weeks of February, the council spent $3000 removing graffiti from its buildings.
It had a ‘‘24-hour removal policy'' to deter taggers.
