Mr Hannan, aged 19, died from massive head injuries after his body was found at around 10.30am on Thursday, less than 100 yards from his family home in O’Malley Park, Southill.
A senior garda source yesterday dismissed reports that a hatchet had been found embedded in the dead man’s upper body.
In fact, no suspected weapon has been located at the scene, he said.
Supt Frank O’Brien, who is heading the investigation, confirmed that a number of people who had been with Mr Hannan at a bonfire near his home early on Thursday have come forward to help the investigation.
Supt O’Brien said the postmortem carried out by the State Pathologist, Dr Marie Cassidy, confirmed that Mr Hannan died from extensive head wounds.
A well-known family who live in the Southill area are understood to be a central element of the murder investigation.
Family members have been moving around Southill on a more regular basis lately, having agreed a truce with a number of others after a spate of gun attacks.
Mr Hannan is thought to have had no criminal connections. It is believed he may have unwittingly got into the company of a criminal element who had been seen near the bonfire.
Mr Hannan’s removal takes place to Holy Family church in Southill on Sunday at 7pm. The burial will take place after 11am Mass on Monday.
Meanwhile, two women and a man arrested in Dublin and Limerick were being questioned last night in connection with the murder last December of Noel Crawford.
A man in his 40s was being held at Mountjoy Garda Station in Dublin and the women at Roxboro and Mayorstone stations in Limerick.