Eight days later, police received a $500,000 ransom demand. They arrested Sannd in Port Waikato and found the Tissot underneath his bed.
Gallery conservator Sarah Hillary, daughter of the late Sir Edmund Hillary, said the robbery had been a "nightmare". "He was waving a gun and hit the security guard violently," she said.
When the painting was found, Hillary was rushed to Pukekohe police station in a car with lights flashing and sirens blaring. She viewed the "butchered" painting, which had been found rolled up in an old sack. "We were in shock - it had been in perfect condition and there it was with all these jagged cuts in it," she said.
"We brought it into the gallery and over the next few days the police would bring us little packages of more pieces as they found them. It was so brittle but I was able to piece the bits together and use them."
Sannd was sentenced to 16 years and nine months in jail.
Last week, the repentant robber walked free from Rimutaka Prison - and this weekend, he sat down to tell his entire, astonishing life story in an interview with the Herald on Sunday.
In that interview, the 61-year-old Sannd reveals that:
He was the driver in 13 armed robberies in Australia, while living in Sydney as a young man. He was never fingered for any of them.
In 1978 he was hired to helicopter into Cambodia with five armed mercenaries, he claims, to photograph evidence of the Khmer Rouge genocide - a botched mission that he says was funded by the CIA.
On his return to New Zealand, he suffered a nervous breakdown and, after police found him with weapons, he was admitted to Oakley [Psychiatric] Hospital in Auckland where doctors administered electro-convulsive shock therapy.
He says he now wants to tell his story, to set the record straight. But Neil Grimstone, the former police officer who arrested him, is not so sure. "He was old school - quite respectful of authority but still one of those old-time crooks," Grimstone said this weekend. "A crook is a crook and he will always be a crook."