A 56-year-old woman was still being questioned by detectives last night about dozens of death threats calls made to politicians including Environment Minister Alan Kelly.
A senior source revealed that the Clondalkin woman who was arrested at around 9am yesterday is co-operating with the investigation.
Gardai believe the female suspect, who has previous form for making threatening phone calls, became "obsessed" with the Irish Water issue after reading media reports.
Detailed garda investigations have revealed that the vast majority of the threatening calls that she made happened over the course of three days between Monday, November 17 and Wednesday, November 19.
It was during this week that the major controversy surrounding the Irish Water debacle spiralled out of control leading to a major government climbdown over the water charges on November 20.
"This woman fed off the media reports which were in circulation that week. She became very fixated and angry with the entire Irish Water issue and it appears that this is what led her to behave like she did.
"Gardai are satisfied that she was acting on her own when she made these calls," a senior source explained.
Among the many menacing calls that she is being investigated for is one on the morning of November 18 to Minister Alan Kelly's office at the Department of Environment's HQ .
When a staff member answered the call they were asked if it was Minister Kelly's office.
After confirming that it was, the caller said: "A bullet will be put in his head before the end of the day. And we'll come down and put a bullet in your head too, you rich f**k. We won't be paying water charges."
When the staff member said they would not listen to false threats, the caller said: "You should listen because you are both scum and who said they were false threats?"
It is understood the woman spoke in a calm and measured way during this call as she issued the threats which happened 24 hours after a woman rang his constituency office in Nenagh, Co Tipperary, warning she would, "bomb you f***ers".
Yesterday, the Herald revealed that the woman is also being investigated for making bomb threats to An Post and threatening President Michael D Higgins and his residence at Aras an Uachtarain as well as Tipperary Fine Gael TD Noel Coonan.
In the case of Deputy Coonan, the threat was made to his parliamentary office at 4pm on November 20 after he compared water charge protesters to Islamic State militants in the Dail.
The female caller gave the TD's secretary a litany of abuse and said: "Tell that fat f***er he is dead and you are dead, too."
A number of other politicians have also been allegedly targeted by the woman who remained in Perase Street Garda Station last night.
These include Labour junior minister for justice Aodhan O'Riordan as well as Clondalkin-based TD Robert Dowds.
Gardai are also investigating whether she made threats last year to offices connected to the European Union.