The Adrian Donohoe murder accused has told the trial he cannot recall what he and another suspect spoke about in two phone calls more than an hour after the fatal shooting.
Aaron Brady (29), who denies capital murder, was being cross-examined for a third day at the Central Criminal Court.
It is the prosecution's case Mr Brady shot Detective Garda Adrian Donohoe (41) dead during the robbery at Lordship Credit Union, the court heard.
Yesterday, prosecution counsel Brendan Grehan SC took the accused through phone traffic of mobiles attributed to him and two other men who are also suspected of involvement but cannot be named for legal reasons.
The court heard the phones of the three men were inactive an hour before and after the murder, and that more than 80 minutes after the robbery Mr Brady received a 67-second phone call from Suspect B.
Asked what they spoke about, he said he could not remember. He also said he could not recall what they discussed in a 52-second conversation 10 minutes later. The jury was told this call was the last activity on Suspect B's phone.
Earlier that evening Suspect B made eight unsuccessful calls to Mr Brady in a short period of time leading up to 8.30pm.
Asked what this was about, the accused said: "How am I supposed to know what that was about?"
It was put to Mr Brady that phones attributed to him and the two other suspects were all inactive between 8.30pm and 10.30pm on the night of the murder.
The Lordship robbery was carried out at 9.25pm.
Mr Brady said he was in a yard in Cullaville loading a trailer and was not with the other two men in this two-hour period.
Counsel also put it to the accused that two people he had not been in contact with since the phones were active again that night were two suspected fuel launders he said he was moving diesel cubes for at the time of the robbery.
Mr Brady said he did not contact them as he only wanted to work at the yard for two hours before going to fix his relationship with Jessica King.
The accused said that, if he had called them, they would have told him to stay and get it done.
Earlier the court was also shown CCTV footage of the Lordship robbery and murder, which was carried out in less than a minute.
After viewing the footage it was put to Mr Brady that it was a "very slick" robbery.
The accused said he would not agree with that but added that from the footage it "happened very fast".
Mr Brady said he could not say if four people seen jumping over the credit union wall and running toward vehicles in the car park moved like young men.
An enhanced audio recording, taken from the dashcam of credit union worker Pat Bellew's car, was also played to the court.
A man can be heard shouting: "Give me the f**king bag, give me the f**king money."
The accused said he could not say if the man's voice was a Border or local accent as he could not make it out.
He was also asked about CCTV footage taken from Cortamlet Primary School in Newry, which showed two vehicles travelling in convoy 40 minutes after the robbery. Mr Grehan said it would make sense that, if the car used in the robbery was being burnt out at nearby Cumsons Road, another vehicle would travel with it to take the people or persons away.
Mr Brady said this would be "for the people who done it" to answer and "it's not for me to comment on".
Mr Brady has pleaded not guilty to the capital murder of Det Gda 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 Mr Bellew at the same location on the same date.
The trial continues today.