Garda Alan Lyne said he saw Niall Fitzpatrick, aged 46, who was not wearing his glasses at the time.
Through his lawyer, it has been continually stated at a criminal trial this week the accused was not at the scene.
Garda Lyne said: “I shouted: ‘Armed gardaí, get down on the ground’. They [three men] appeared startled for a moment, they went to run. They went over this wall [indicated photograph to the court]. Two of them got over successfully. A third man stumbled and fell as he went over the wall.
“I set after [another man] and Niall Fitzpatrick. I saw a long object in Niall Fitzpatrick’s right hand. It was dark in colour. I stopped before I got over the wall and threw a stun grenade into the field. It went off. After that I followed him.
“They kept running up this field until I could see them coming to a gate. They both went over this gate. I was a good number of metres behind… I lost sight of [them].”
Defence senior counsel, Brendan Nix, said: “In the briefing before this you were told my client was going to be there.”
Garda Lyne replied, “Among others, yes.”
Mr Nix asked: “Why did you not shout, ‘There is 10 of us here who know you Fitzy, drop the fecking gun or I will drop you’?” Garda Lyne said he shouted: ‘Armed gardaí, get down on the ground’ and that the accused had plenty of opportunity to stop.
Mr Fitzpatrick of Corrin Close, The Glen, Cork, denies charges of possession of a Remington 12-guage pump-action shotgun and ammunition, and attempted burglary and attempted aggravated burglary at the home of Patrick Glavin at Rougrane, Glanmire, Co Cork, on August 11, 2013.
His trial before Judge David Riordan and a jury of six men and six women continues at Cork Circuit Criminal Court.