Koretz's swindling career began in 1905, when he forged and sold a series of mortgages on non-existent properties, using the proceeds in a Ponzi scheme to cover interest payments and finance an opulent lifestyle.

In 1911 Koretz began selling stock in the Bayano River Syndicate, which he claimed controlled millions of acres of prime timberland in a remote region of Panama.

He purchased and renovated the secluded Pinehurst Lodge near present-day Kejimkujik National Park, in southwestern Nova Scotia, where he lavishly entertained a new circle of friends that included the future Canadian author Thomas Raddall.

Koretz never crossed paths with another Nova Scotia visitor, the adventure novelist Zane Grey, whose work he falsely claimed credit for promoting among New York publishers.

Koretz was identified and arrested in Halifax on November 23, 1924, through a suit he had brought to a tailor for repair of the lining, on which a label with his real name was sewn in along with the name of the Chicago clothier from whom it had been purchased.