The senior detective who oversaw the Adrian Donohoe murder investigation has described the accused's account of his movements on the night of the killing as "bunkum and lies", the Central Criminal Court heard.
Retired Detective Inspector Pat Marry, who was the senior investigating officer (SIO) until 2018, was giving evidence in the trial of Aaron Brady who denies capital murder.
Mr Marry told the jury that he did not ask the PSNI to search a diesel-laundering yard where the accused said he was on the night of the robbery.
He said he had no confidence in what Mr Brady "was telling gardai because I believe he was involved in the murder of Adrian Donohoe and was in the car park of Lordship Credit Union".
Mr Brady has pleaded not guilty to the murder of Mr Donohoe (41), who was then a member of An Garda Siochana acting in the course of his duty, at the credit union in Bellurgan, Co Louth, on January 25, 2013.
Mr Brady (29), of New Road, Crossmaglen, Co Armagh, also denies the robbery of approximately €7,000 in cash and assorted cheques from Pat Bellew at the same location on the same date.
Yesterday Mr Marry was cross-examined in relation to a yard on the Concession Road, in Cullaville, Armagh, where Mr Brady said he arrived shortly after 8pm on the night of the murder before leaving 15 minutes later after failing to start a forklift.
The court previously heard that he told two detectives this in an off-the-record account 10 days after the robbery, and that last December a formal alibi was served on the prosecution saying this was incorrect and that he was moving laundered diesel cubes at the yard for between 90 minutes and two hours.
Mr Marry told defence counsel Michael O'Higgins SC that CCTV footage from Concession Road was viewed and that a car belonging to Suspect A, who Mr Brady said he was with that night, did not show up.
Mr Marry said the CCTV review was of "not great" footage. The court heard that cars were filmed outside the store on eight occasions but none could be identified.
"So that was very evident to me that the story told by Aaron Brady was bunkum and lies," he said.
Mr Marry told counsel that the PSNI was not asked to go to this site and that a sergeant was liaising with them in relation to this matter.
He agreed that he had previously received permission from the PSNI to send gardai across the Border to examine a particular site in another investigation.
Asked what was different about a diesel-laundering site, Mr Marry said: "Because as I said, that site had no relevance to me as SIO because I believe Aaron Brady was not there."
It was also put to him that phone traffic between Mr Brady and a number of other people, including a known fuel launderer, in and around the week of the murder would appear to relate to fuel laundering.
Mr Marry said this was the account given by one of the known fuel launderers to gardai, adding: "But do we believe him."
The cross-examination will continue before the jury of six men and seven women this morning.