Traffic restrictions in the town are expected to be lifted this afternoon as a man in his 40's remains in Garda custody in connection with the incident.
The period of detention for the suspect in the murder of Detective Garda Horkan is likely to be extended this afternoon, as investigations continue into the shooting dead of the 49-year old.
The suspect, who is in his 40's and from the wider West Roscommon area remains in custody today, following his arrest in the immediate aftermath of the shooting at around midnight on Wednesday.
The man has been described as being known to Gardai, but not involved in any criminality.
Technical examinations were carried out yesterday and again today at the scene and it is hoped that they will conclude after lunchtime to allow the town re open fully to traffic.
Preparations are also under way for a State funeral for the Detective and his body will be returned to his family home in Co. Mayo today.
Books of condolence have also opened at Garda Stations across the country.