What jogged the memory of the taxi driver who picked up Blathnaid on the night she disappeared, and why did he take so long to come forward?
The driver could not recall picking up Blathnaid and had to check through records to confirm where exactly his taxi was on the date of Blathnaid's disappearance.
It took some days to access the records.
When he received his files last week, they confirmed that he was on Sir John Rogerson's Quay on the day in question and confirmed he had dropped her to Howth.
She withdrew €60 from the ATM, most likely to pay for the taxi trip to Howth.
She was last seen being dropped off on Harbour Road in Howth village.
No. Blathnaid left her phone behind her in her apartment and banking records show that she has made no further withdrawals from her bank account.
Officers took possession of Blathnaid's computer following her disappearance.
Detailed analysis of the computer's hard-drive, her internet activity and searches prior to her disappearance led garda investigators to dismiss any suggestions of foul play being involved.
Gardai have begun their third day searching the water around Howth and have extended their search up and down the east coast -- by helicopter -- after examining tidal movements and interviewing experienced fishermen from the area.
The gardai continue to appeal for anyone who may have seen Blathnaid on Harbour Road in Howth from 8.30pm onwards on Tuesday, December 14, to contact them on 01 6669500.