Trevor Sargent was still in contact with gardai as late as last week about the affair which cost him his Ministerial job.
The former Minister wrote to a Garda Superintendent on Monday of last week seeking privileges for his constituent.
Mr Sargent wanted the senior garda to “keep an eye” on his constituent in court.
It undermines the former Green Party leader’s claims that he only remembered the case when he read about it in this newspaper last night.
The correspondence seen by the Herald shows that Mr Sargent went much further than his Dail admission last night -- in which he denied contacting senior gardai in the first instance.
Mr Sargent also implied that he had no contact with the force in the last two years in connection with the case.
He said only he contacted the individual garda involved because he did not want to undermine the officer by going to her superiors.
Now a letter carried in today's Herald shows he was in contact with Superintendent Joe Kelly of Balbriggan garda station right up until Monday, February 15 last.
The Herald can also disclose he was in contact with the garda's superiors soon after writing the letter to the officer which cost him his Ministerial position.
The Green TD claimed last night that he did not make contact with a superintendent, but the emergence of new letters disproves this.
In the wake of his resignation, Mr Sargent also said that the case only "came back" to him after the Herald exclusive.
However, the controversy is set to deepen further as we can now disclose details of another letter personally signed by former Minister for Food just last week.
A spokesperson for Mr Sargent played down the new letters today saying: "The point was that his initial contact was with the gardai.
"The most recent letter bears out his original contention that he was worried about the man and that there could be more violence in the area," he added.
Mr Sargent claims he tried to deal with the case "in as low-key a fashion as possible, not hiding it, but writing to the garda in question, not to the superintendent".
However, the Herald has now seen another letter which shows that subsequent contact did take place between Mr Sargent and a superintendent.
Nine days ago the TD wrote to Superintendent Kelly in relation to "his previous correspondence".
The contents of the letter bring an explosive new element to the row, with opposition TDs now demanding a "detailed, on the record account of Mr Sargent's involvement in criminal proceedings".
Fine Gael says it shows that the former Green Party leader had "no choice but to resign".
Mr Sargent last night defended his intervention in the case of Balbriggan man Dominic McGowan who has been convicted of threatening and abusive behaviour.
In June 2008, the TD wrote to an individual garda advising her that issuing a summons against his constituent was "wholly inappropriate".
A second letter to Mr McGowan noted that if a reply from the officer was not forthcoming, he would "go further with the matter".
Last night, Green Party leader John Gormley said that he was "shell-shocked" by the Herald story, while Mr Sargent attempted to defend his role in the saga.
"My only motivation was to help an individual who felt very vulnerable, who feared for his own safety and simply wanting to see justice be done," he said. He admitted that he "overstepped the line".
His spokesperson has now confirmed that Mr Sargent was actively involved in the case just last week -- days before an appeal by Mr McGowan's assailant came before the court.
Mr Sargent addressed a letter to a superintendent and said that he would be grateful if the senior garda would "keep an eye on the case".
The letter states: "I fear for the safety of Mr McGowan who faces his attacker in court again in the Central Criminal Court this Friday, 19th February 2010 as a witness to his own attack in September 2007."
Previous letters revealed by this paper were signed on behalf of Mr Sargent, but the most recent correspondence was signed personally.
Mr Sargent now faces a new series of damaging questions with Fine Gael calling for a more upfront explanation.
The opposition justice spokesperson Charlie Flanagan said that the new information shows the TD had "no choice but to resign".