French police confessed to being clueless over the whereabouts of the portrait, which remained in Picasso's private collection until his death in 1973.
But when Brand, whose previous finds include a pair of bronze horses sculpted for Adolf Hitler, put out word on the street that he was looking for the portrait earlier this month, he was contacted by "two persons with good contacts in the underworld". They told him the painting was in the Netherlands.
"Two representatives of a Dutch businessman contacted me, saying their client had the painting. He was at his wits' end," said Brand.
"He thought the Picasso was part of a legitimate deal. It turns out the deal was legitimate - the method of payment was not," Brand told AFP.
He called the Dutch and French police who said they would not prosecute the current owner.
"Since the original theft, the painting must have changed hands at least 10 times," he said. It had entered the criminal circuit, where it circled for many years "often being used as collateral, popping up in a drug deal here, four years later in an arms deal there".
Brand said he had to act swiftly, otherwise, the painting may have disappeared back into the underworld. "I told the intermediaries, it's now or never, because the painting is probably in a very bad state... We have to act as soon as we can."
Then two weeks ago, they delivered it "right to my door". He then hung the Picasso on his wall. "The urge was too great; I couldn't resist," he said, adding that it made "my apartment one of the most expensive in Amsterdam for a day".
A Picasso expert from New York's Pace Gallery flew in to verify its authenticity at a high-security warehouse in Amsterdam. Also present was retired British detective Dick Ellis, founder of Scotland Yard's art and antiquities squad, representing an unnamed insurance company.
"There is no doubt that this is the stolen Picasso," Ellis, who now runs a London-based art risk consultancy business, told AFP. Buste de Femme is back in possession of the insurance company, which now had to decide the next steps, Brand and Ellis said.
It was unclear whether the latest owner would be reimbursed at all for the work while Brand said that he will probably receive no payment for his pains.
"At the time there was a reward offered of €400,000 and I don't know if the reward will be paid," he said. "If there is a reward, it should go to the people who brought it in. My reward was to have a Picasso on my wall for one night. I can tell you, it was great."