Potsby-Mahn was a gold digger who had been widowed three times, allegedly from killing her spouses and getting rich from the life insurance they left her. When Jack Potsby, who was a typical loser, won a huge sum of money, she decided to marry him. Like all her previous spouses, he had set up life insurance for her out of love. Because Potsby had the tendency to spend money quickly, Goldie noticed his debts would go over his life insurance payout. Because of this, Potsby-Mahn hurriedly plotted to kill her husband.
She forged a knife made of ice, using a scrap of paper as a mould, then used the knife to backstab him. To make the murder seem like it was a burglary gone wrong, she smashed the window from outside, causing the glass shards to land atop Potsby to fabricate the scene of crime. She quickly cleaned the knife using a towel, left the towel on the balcony and had the knife melted in a pot cooking pasta.
When the security guard Chase M. Downes heard the sound of glass breaking, he quickly rushed to Potsby's flat. Potsby-Mahn then lied to him that she had been taking a shower when she suddenly heard the sound of her husband scream, only to see a muscular man dressed entirely in black fleeing the scene.
Downes quickly searched the area and caught a well-known burglar named Buster Nicks. The burglar claimed he was planning to break into a ground-floor flat but when he heard the sound of glass breaking, he thought it was another burglar (though he did not see anyone come down) and decided to call off his plan. Nevertheless, Goldie's ploy worked for a time as Buster Nicks found himself apprehended for the burglary-murder.
After Nicks was caught, she started dating again and found a new boyfriend named Bingo, whom she treated like a pet, going so far as to buy him a spiked collar. During the investigation conducted by the Mystery Room, she was called in to help with the investigation by Inspector Alfendi Layton. When she brought Bingo with him, Alfendi asked him to leave, with Potsby-Mahn ordering him to go home and wait for her under the porch.
As the Mystery Room began to tie up the loose ends of the case, she insisted vehemently that Nicks must have done it due to the broken window and the fact that he was the only burglar present at that time. She was later accused of murdering Potsby when called in for a second questioning. Goldie was sure that neither Lucy nor Alfendi would be able to figure out the murder weapon, however they determined through various inconsistencies (such as a pot of pasta being cooked despite the known lack of cooking skills from the Potsby couple) that Goldie had been using a knife made of ice, and fabricated the burglary. Goldie's earlier vehement claim of never having left the apartment now worked against her, as it became clear given the circumstances that she was the culprit.
Goldie demanded to see her lawyer before being questioned further, but later confessed to killing Potsby for the life insurance payout. She was soon convicted of the murder and was placed in a prison cell. Bingo looked over at her by the window as she sighed about her predicament.
- Her name is interpreted as, "goldie pots be mine", due to the fact she married men who were rich so she could take their life insurance money.
- As she has the last name of "Potsby-Mahn", it can be assumed Mahn was either her maiden surname, or one taken from a previous marriage.