Gardai responded to a 999 call at a house used by two men allegedly involved in the murder of Adrian Donohoe four days before the fatal shooting, a court has heard.
The emergency call - made in the early hours of the morning - reported three suspicious males at the Louth home around a mile from the Lordship Credit Union where the detective garda was shot dead.
Yesterday the Central Criminal Court heard from gardai who responded at around 4.40am on January 21, 2013, but didn't find any intruders.
The jury previously heard that Aaron Brady, who denies capital murder, had stayed at the property around the time of the killing, along with another man who the prosecution say was also involved but cannot be identified for legal reasons.
Mr Brady (29) is on trial for the 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, Co Louth, on January 25, 2013.
The accused, of New Road in Crossmaglen, Co Armagh, is also charged with the robbery of about €7,000 in cash and cheques from Pat Bellew at the same location on the same date. He has pleaded not guilty to both charges.
Gda Fergal McCarthy said he was on duty in the Louth divisional control room, at Drogheda Garda Station, in the early hours of January 21, 2013.
He said he received a call on the emergency line at 4.38am from a man who identified himself and said he lived at an address near Bellurgan in Co Louth.
The court heard this man said he spotted three males dressed in black clothing in the yard of the house.
Gda McCarthy said he forwarded this call on to the radio control room in Dundalk.
Gda Damien Welby gave evidence that he was on patrol when he received a call about a possible trespasser and arrived on scene at 4.45am.
He told the court he made his way to the property and met two men in the house, which included the person who made the emergency call.
Gda Welby agreed with Lorcan Staines SC, prosecuting, that the men said they heard noises and when they looked outside they saw what they believed to be a person wearing all black. This individual was alleged to have been near a container at the rear yard.
The court heard that gardai carried out an inspection but noted there was no damage to the lock of the container.
He said they checked the grounds and didn't notice signs of footprints or suspicious vehicles parked nearby.
Garda Robbie Peelo said he arrived in a separate patrol car a short time before Gda Welby
He said he spoke to a male who identified himself and reported seeing a man dressed in black at the rear of the house.
They conducted a search of the yard and spent between 10 and 15 minutes there but found nothing suspicious.
Gda Peelo also recalled commenting to his colleague at the scene that there were no footprints on the grass at the property when they initiated their search.
The witness said it was "clean" and that there was heavy dew on the grass but no footprints.
The Central Criminal Court also heard evidence of mobile numbers being attributed to nine people as part of the investigation.
Det Gda Colin Compton, of Dundalk Garda Station, gave evidence of attributing three of these phone numbers to Aaron Brady.
One of these, linked to his Facebook account, was registered under the name 'Lexi' and had a date of birth given as February 1999 with an address in Armagh.
The trial continues.