She went missing off the yacht about 40 nautical miles south-west of Rarotonga in late August.
Roehrs, sold the Zangano for the price of a plane fare and earlier this week flew out of the country.
Last week he left the port of Avatiu, where he had been living on the 54-foot ketch, at night and the next morning sent a distress signal saying his vessel was sinking.
The police patrol boat Te Kukupa sped to his rescue and he told the Maritime Police the boat was not worth saving and to let it sink. He said it was not insured.
Sources have told the CI News officers thought the man’s behaviour very suspicious.
The police sent a salvage team aboard and used a handpump to keep the steel-hulled yacht afloat while it was towed back to Avatiu.
There the Puaikura Volunteer Fire brigade used their pump to empty the remaining water out. When firefighters went below deck to assess the situation the water was up to the galley’s bench plates.
One of the firefighters has told CI News that a hose in the forward toilet had been cut and water was entering the yacht there and via an open sea-cock that was running into the bilge.
The fireman said he had no doubt Roehrs was trying to sink the boat.
That story has been backed up by new owner Keith Christian, who agreed the hose had been cut and that when Roehrs sailed from Avatiu all the food he had on board was two apples and three bananas. He had no bottled water.
When Roehrs originally arrived on Rarotonga he is believed to have told authorities he searched for his missing girlfriend for two hours but, with his yacht running low of fuel, decided to head to Avatiu Harbour where he tied up overnight before reporting her disappearance.
On his way into port he collided with a freighter and had to be helped to dock by the tug Toa.
Police later arrived at the Zangano and removed items, including a laptop.
Roehrs, who is also known variously as Alex MacKinnon, Alex Mackinnon Roehrs and Oskar Roehrs, is an expert computer programmer. He has also written a novel called Crashing Johnny’s Party.
Christian told the CI News there were very few women’s belongings on the yacht when he went through its contents after buying it.
“There were two pairs of women’s shoes – different sizes, not much else. There was no women’s clothing, no toiletries and no passport ...”
Christian said the police had Roehr’s laptop for some time, “but he is a computer expert … he writes computer programs. It was a waste of time local cops looking at it. He’d have wiped the computer”.
“I checked all his GPS courses and they have been wiped.”
And Roehrs had more than one laptop on the yacht.
“Well, that’s the thing. The cops took his computer, but he was down there in the cabin every day I was there, on his computer.
“He had another one, or two …”
Christian did some work on the yacht for Roehrs. “When I was first on the boat he said the radio wasn’t working, but I was a little bit suspicious as it was brand new and so I pressed the button and it sparked up immediately.”
“When he first got here I asked him, ‘did you sail it yourself?’ And he said, ‘I have a lot of trouble with crew members.’
“Later I asked if she fell overboard and he said ‘yeah’.”
Christian said Roehrs initially said the missing woman was his girlfriend, but the next day said it was his wife.
“I’ve looked through the weather reports and it was calm for days all around that day. The boat was about 40 miles out of here, that’s what he told me.
“The VHF on that boat is a good one – worked from 24 nautical miles out the other day didn’t it? It’s a 30nm radio (so) why didn’t he motor 10 miles and then call up she was missing?
“Instead, he motored all the way down here and stayed for a night in the port before he even reported it.
“There’s another half day gone. That’s dodgy.” Roehrs has two passports – an Australian one and a Chilean one.
When asked where he could have flown to, Christian said: “He could be anywhere.”