Two men arrested in connection with the shooting dead of Mr John Ryan in Limerick city last night have been released without charge.
However, gardaí in Limerick remain on high alert and armed patrols are expected to try and prevent any escalation of the feud between the Ryan and Keane families in the wake of the killing.
As fears grew of an escalation of the feud Garda Superintendent Willie Keane appealed to those involved to stop.
He said: "Stand back. Stand back from the brink and let the gardai deal with the matter."
Mr Ryan was killed in a drive-by shooting in Thomandgate, in the north of Limerick city at 6.30 p.m. yesterday. A motorcycle used in the attack was recovered last night, a Garda spokesman confirmed. "It has been taken away for technical examination," he added.The dead man was the brother of Mr Eddie Ryan - who was murdered in the Moose Bar, Limerick, in November 2000, and an uncle of Eddie and Kieran Ryan whose alleged abduction in January led to an escalation of the feud.
Kieran and Eddie jnr - were the victims of an alleged kidnap which led to a massive Garda manhunt. However, they turned up safe at a Garda station in Portlaoise a week later.
Late last night there were reports of more shots being fired in the Garryowen area of the city and of a mini-riot in Island Field.
There were also reports of an attempt to attack a house belonging to members of the rival Keane family.
Gardai fear the killing will spark a further escalation in the vicious feud which is believed to have led to the murder of Mr Kieran Keane in January this year and to more than 100 other "serious" incidents.