Keenan Johnson has rebuked a Garda in a written report for ''incomplete evidence'' in a drugs case.
The judge was not told the woman was making €2,000 a month selling drugs, that she was using them herself.
Judge Johnson from Ballymote was also not told in court that the woman had been separately rearrested days earlier in a drugs related case.
He had been misled, the judge said and the Garda involved had shown ''a grave error of judgement.Judge Johnson accepted that the Garda was motivated by trying to help the woman.
She had heroin on her in court that day, to use if she had been given a prison sentence by Judge Keenan, it has also emerged.
The woman, aged 39, avoided a "likely" prison sentence because of the incomplete evidence, said Judge Johnson in his written summary of the June 2016 case in the midlands.Considerable Concern
The summary has now been seen by RTE which presented the details on its ''This Week'' radio show yesterday, Sunday.
Judge Johnson wrote it was of "considerable concern" to him that the garda had withheld critical information about the drug dealer from his court, relating to what the judge described as "very serious offences".
The Garda had given him the "clear impression" at a sentencing hearing for a drugs offence last June that the 39-year-old woman had a one-off involvement in the drugs trade.
This, wrote Judge Johnson, was despite the garda having personally recorded an admission from the woman three days earlier that she was making around €2,000 per month selling drugs.Cocaine, Heroin
She made the admission to the Garda after she was again caught in possession of both heroin and cocaine for sale or supply.
The judge made his remarks nine days ago at Mullingar Circuit Court when sentencing the woman for possession of €1,600 worth of cocaine and heroin.
The judge also said that his court was told the woman, who was also a drug user, was drug free on the date she was being sentenced in June 2016.
In fact she had disclosed to the Garda (giving evidence) that she even planned on bringing some of the heroin found in her possession with her to the court to have as a "supply to smoke" if she got a custodial sentence.
At the time the Garda gave evidence to the court [at the June 7th 2016 sentencing hearing] ''he was aware the accused had been apprehended" three days beforehand,'' the judge said.Full Picture
He said: "Not alone that,'' but on June 4th the accused had given an interview to the Garda….. and had made full admissions concerning it.
"It was a source of considerable concern to me when I was advised that this offence occurred, a mere three days before the previous offence was dealt with by this court on June 7th 2016.""At no stage during these proceedings was I made aware of the fact that a mere three days before June 7th the accused had been involved in serious reoffending.
''Indeed I am satisfied that I was misled in relation to this matter," the judge said in his written record.
He said: "In my view he [the Garda) made a grave error of judgment in not telling the court the full background on the date of the sentencing hearing.
He ''had an obligation to give the court a full picture of the situation and not allow the court to proceed on the basis that there had been no [re]offending by the accused."
He said that at least 80% of the cases which come before his court were now drug related.Judge Johnson said he accepted that the garda had made an error and said he also accepted the garda's explanation that he was motivated by trying to help the woman.
However, he said that "the court in imposing sentence has to be in possession of all the facts in order to secure a sentence that is both fair and proportionate.''
Had the court been aware that the accused had re-offended "she would likely have been given a custodial sentence,'' Judge Johnson said.
He said that the re-offending had completely undermined the representations made to court that she had stayed out of trouble and was drug free.