Technical experts are still working on CCTV footage which appears to show the man suspected of carrying out the attack on the two girls, aged four and six.
The two little friends were cycling near their homes in Cherry Park in Swords shortly after 5pm last Saturday, when a man took them both by the hand and brought them to the side of a vacant house and assaulted them.
Detectives leading the investigation appealed directly to people who think they might know the suspect to ring them as soon as can tin order to assist them.
“My appeal is to anybody who knows this individual — people he might have shared information with — even if they just think they know his identity, to come forward and help us find him,” said Detective Inspector Walter O’Sullivan.
He described the attacker as a “sinister individual” who may have struck before and could strike again.
Gardaí have described the man as aged 20 to 30 years with short brown hair, a distinct pointed nose, unshaven with a possible slight beard. He wore a dark pin-stripped suit with a white shirt and black shoes. He may have a Dublin accent.
One of the fathers of the two victims said he suspected the attacker had carried out some planning and may be a local as he knew the house he had taken the girls to was vacant.
Gardaí have a working theory that the attacker did know the area and knew the house was vacant.
However, they have not ruled out the possibility he might have been an opportunist.
Officers said the CCTV footage they had retrieved was of particular importance as it established the truthfulness of the allegations and gave them information on the suspect.
However, gardaí say the images are of poor quality and need to be further enhanced.
Anyone with information is asked to ring Swords Garda Station on 01-6664711 or the Garda Confidential Line on 1800-666-111.