A labourer who denies the capital murder of Detective Garda Adrian Donohoe has said he was loading waste from laundered diesel at the time of the fatal shooting.

The Central Criminal Court heard that in a notice of alibi supplied to the Director of Public Prosecutions (DPP) dated Monday, 17 February, Aaron Brady gave the address of a yard on Concession Road in Cullaville, Co Armagh.

He said he spent between 90 minutes and two hours there loading "diesel waste cubes" onto a truck on the evening of 25 January, 2013 around the time when the detective was shot.

Mr Brady said he had previously given gardaí an untrue account of his movements out of fear he might incriminate himself over diesel laundering.

Mr Brady, 29, from New Road, Crossmaglen, Co Armagh has pleaded not guilty to the capital murder of Det Gda Donohoe, 41 on 25 January, 2013 at Lordship Credit Union, Bellurgan, Co Louth.

Mr Brady has also pleaded not guilty to a charge of robbing approximately €7,000 in cash and assorted cheques on the same date and at the same location.

Under cross-examination Detective Inspector Mark Phillips told defence counsel Michael O'Higgins SC that gardaí were aware of the alibi since 20 December this year.

Insp Phillips read the notice of alibi in which Mr Brady said that on 5 and 6 February, 2013 he attended Dundalk Garda Station where he gave a voluntary statement detailing his movements on the night Det Gda Donohoe was shot.

While giving that statement he said his solicitor told gardaí that he was reluctant to account for his movements for fear that he might be prosecuted.

Gardaí assured him that all they wanted was a true account and agreed that they would not include anything about diesel in his statement.

But Mr Brady said he was still unsure of whether he would incriminate himself. He then told gardaí that he was at the yard on Concession Road where he was supposed to load purple cubes of laundered diesel onto a truck but was unable to do so because he couldn't get the forklift to start and left without loading any cubes.

This was not correct, he stated in the alibi notice.

He added: "I went around 8 o'clock with the sole intention of loading a large volume of diesel waste cubes on to a curtain side lorry." He said he had been told by two men to load as many cubes as possible. When he arrived, he said, he "hopped" over the gate and into the yard, which he said was in "complete darkness".

The forklift failed to start so he got some Easy Start and sprayed the filter. The forklift started and he began loading two cubes at a time, placing them on the floor of the lorry.

He said the process took about 90 minutes to two hours "due to rough terrain and poor lighting and the forklift cutting out due to poor weather conditions." He later contacted the people who asked him to load the cubes to tell them he loaded as many as he could.

Inspector Phillips agreed with Mr O'Higgins that the accused man has previously received a 12-month sentence for criminal damage, dangerous driving and unauthorised taking of a vehicle.

He said this was Mr Brady's only custodial sentence. The Brady family, he said, is from Monaghan originally and his father is a physio for Crossmaglen Rangers, a "very, very successful GAA club."

He agreed that Crossmaglen is known as a "Republican stronghold" and some people there are suspicious of authority and that there are reports of "diesel activity" along the south Armagh border.

He further agreed that people would be reluctant to discuss diesel laundering with the gardaí and "doubly reluctant" for that to be public knowledge. He said a person's personal safety could be compromised if it was known they were talking about it.

Asked if there were "massive profits" to be made he said diesel laundering is done for profit.

Earlier the court heard from the statements given by Mr Brady to gardaí in February 2013.

Inspector Phillips said the accused described his occupation as "labour worker" and gave an account of his movements from the Wednesday two days prior to the shooting and on into the following week.

Towards the end of the second interview Mr Brady said: "I just want to say why I came in to the garda station yesterday and today. I came in to make a statement to hopefully clear my name. That's it."

The trial continues in front of Justice Michael White and a jury of eight men and seven women.