The man accused of the murder of a garda said the first time he heard about it was on social media an hour and a quarter after it happened.

Aaron Brady was challenged today on the issue of when he first heard about the murder of Detective Garda Adrian Donohoe.

Mr Brady denied that he had told a garda sergeant who stopped him the following day that he did not know that a garda had been shot.

In court today he blamed his senior counsel for not challenging the sergeant when he also gave that evidence during the course of the trial.

The 29-year-old from New Road, Crossmaglen in Co Armagh, has pleaded not guilty to the murder of Det Donohoe and to a second charge of robbing €7,000 in cash and cheques at the Lordship Credit Union on 25 January 2013.

He said today he first heard about it in his 17-year-old girlfriend's house at around 10.45pm on 25 January 2013, around an hour and a quarter after it had happened.

Her friend saw it on a computer on Facebook in the bedroom.

He said he then went downstairs and saw on the RTÉ News a short time later that it had happened at the Credit Union in Bellurgan and knew exactly where that was.

The following day he and his friend were stopped by gardaí and Sergeant John Moroney asked him to account for his movements around the time of the murder and robbery.

He admitted he lied to gardaí then but denied telling the sergeant that he did not know a garda had been shot.

The court heard the sergeant thought it was a strange thing to say, he put it in a report and also gave sworn evidence in the trial.

"I didn't say that", Aaron Brady said today. "It's ridiculous, I  was fully aware a garda was murdered when he stopped me".

When asked today why he did not challenge Sergeant Moroney's evidence when he was in the witness box during this trial he said he wanted to but his senior counsel Michael O' Higgins did not.

"My senior counsel didn't want to challenge it," he said.

He also admitted today several lies in a lengthy statement he made to gardaí over two consecutive days shortly after the murder.

He admitted he had a second phone for diesel laundering, which he did not tell them about.

He said he was unhappy with the garda investigation, which he said made "no mention" of his claim of being in the yard diesel laundering at the time of the murder.

He also admitted that he told his then-girlfriend to lie about his whereabouts on the night of the murder.

The 17-year-old did that when the PSNI called to her house the following day.

However, Aaron Brady said today that after that visit he told her to tell the truth before she went to the police station and made a false statement about him.

"I told her to tell the truth". He said that he told her "this is very serious".

He also said today he was "very worried" that she "had told lies" but admitted that he had asked her to lie.

He said he did not think the PSNI were going to call. "I told her to tell the truth," he said today, "I told her, I promise you".

He said today he could not say why she had gone to the police station and made a false statement after he had told her to tell the truth. 

The 17-year-old subsequently retracted her false statement and made another statement to gardaí in Dundalk six days after the murder.

Her friend had also made a false statement to the PSNI but she first went back the following day and corrected it.