Aaron Brady has denied he was testing garda response times five nights before the Detective Adrian Donohoe murder when officers were called to his friend's home near the scene of the fatal shooting, the trial has heard.
The accused was being cross-examined for a second day at the Central Criminal Court yesterday about his movements on the week of the robbery.
He admitted telling several lies to gardai, which he says was to hide the fact he was moving laundered diesel cubes that evening, but denied any involvement in the murder.
He was asked by prosecution counsel Brendan Grehan about gardai being called to the home of Suspect A, his friend who is also a suspect in the robbery of, and lived close to, Lordship Credit Union, in the early hours of January 21, 2013.
Mr Brady (29) told the court he was staying at the property that night when he was woken by a bang. He said when he looked outside he saw two men in the garden.
The accused told the jury he wanted to go out to check what was happening, but Suspect A's brother called gardai.
Mr Grehan said officers had given evidence that when they arrived there was heavy dew on the grass but no footprints indicating anyone had been there.
It was put to the accused that the call was to see how long it would take for gardai to get to the property near Lordship Credit Union.
Mr Brady replied: "No, that's ridiculous."
Mr Brady agreed with Mr Grehan that he left for the US days after his home was searched as part of the investigation in April 2013.
The court heard he had applied for a British passport and that it arrived the day police officers were at his family home in Armagh.
Mr Grehan also took the accused through mobile phone evidence and CCTV footage three nights before the fatal shooting when a car, which the prosecution says was used in the credit union robbery, was stolen in Clogherhead.
He said he would "fully disagree" that Suspect A's car was captured on CCTV close to the scene of the "creeper burglary" that morning.
Mr Brady said Suspect A was making "six figures" in the US and he "is a wealthy man".
"What in God's name would he be doing robbing cars and committing armed robberies? What in God's name?" he added.
Mr Brady has pleaded not guilty to the capital murder of Adrian Donohoe (41), who was then a member of An Garda Siochana acting in the course of his duty, at Lordship Credit Union in Bellurgan, Dundalk, Co Louth, on January 25, 2013.
The accused, of New Road in Crossmaglen, Co Armagh, also denies robbery of around €7,000 in cash and assorted cheques from Pat Bellew at the same location on the same date.
The cross-examination will continue this morning.