Charlotte Roche was found guilty of stealing thousands of pounds from a Scottish car dealership.
Her latest conviction came just months after dodging jail in England for scamming her ex-boyfriend out of more than £14,000 by convincing him she had cancer.
She also pocketed €30,000 from her former employers back in her native Ireland in a previous con.
Despite her two previous convictions, Roche - who denied the latest charge - was said by prosecutors to be a first time offender when she appeared at Aberdeen Sheriff Court last month.
She was found guilty after a three day trial of stealing more than £3,000 from a motor business in the city.
The 31-year-old, who is now unemployed, stole the cash during her five weeks working for John Clark BMW garage between November and December 2014.
But Sheriff Eric Brown quickly found a number of discrepancies in the social work report that was presented to him at the sentencing - including fake claims that she had completed a degree in business administration.
He then brought up the previous cases involving Roche in England and Ireland and demanded an investigation into why the court was not made aware of her criminal history up until now.
Sheriff Brown said that since the trial concluded he had found out through media reports that Roche had previously embezzled more than 30,000 euros from a crash repair shop just outside Dublin.
The sheriff said that he had been led to believe that she had appeared in an Irish court in late 2011 and 2012 in relation to the offence but he was unsure if she had admitted the crime or had been found guilty after trial.
Aberdeen Sheriff Court heard that her crime related to 136 customer payments to Ace Autobody Repair shop that Roche had failed to pass on to her bosses.
Sheriff Brown then told her solicitor, who had no knowledge of the Irish scam, that Roche had also dodged jail in England earlier this year despite defrauding a man she met on a dating site.
She met her English victim, Matthew Pilgrim, on dating website Plenty of Fish in April 2014.
She later told him that she had financial problems and that she was seeing a specialist over fears she had ovarian cancer.
Roche claimed she needed surgery to remove a growth and that she could avoid a six month wait for surgery on the NHS by paying to go private.
Feeling under pressure, Mr Pilgrim agreed to lend her thousands of pounds.
He went on to lend her more money for post-op care but eventually he realised the relationship was over and that he had been duped
Roche avoided jail but was given a six-month suspended sentence at Maidstone Crown Court in February.
Addressing her current defence agent Stuart Murray, Sheriff Brown said: “It appears to me that the true circumstances of your client’s history may be very different from the history that is outlined in the Criminal Justice and Social Work report.”
Roche, whose address was given in court papers as Aberdeen, had her sentence further deferred until next month pending investigations into the previous court appearances by the Crown and the defence.
She was remanded in custody meantime.
Turning to Roche, who still protests her innocence, Sheriff Brown added: “As far as you’re concerned I simply do not know what to believe.
“I do not think it would be in the public interest to release you on bail given the pending investigations.”
Aberdeen Sheriff Court heard last month that garage boss Raymond Henderson grew suspicious of the service assistant after she suddenly took ill with a ruptured abdominal ulcer on December 16, 2014, and was rushed to hospital - just after he was informed of missing customer payments.
A number of witnesses claimed to have handed over cash for garage services to a woman matching Roche’s description in the weeks before her hospitalisation.
However, the accounts department later found the cash and invoice slips were missing from the petty cash box - all of which should have been deposited in Roche’s name.
Mr Henderson eventually convinced her to pay back £1,000 just before Christmas after getting her to confess over the phone.
But Roche claimed during the trial that she felt pressured into giving Mr Henderson a false admission of guilt while she was under the influence of strong medication.
And she tried to claim she was being “framed” by colleagues who had set her up.
Sheriff Brown said he had not found her evidence “credible or reliable”.