It started with a fancy watch nabbed at Halifax's international airport.

But newly released search warrants have revealed the intricate sleuthing that led immigration officials to dive deeply into how hundreds of business immigrants used the same home address in P.E.I.

On Monday, charges were laid alleging siblings Ping Zhong and her brother, Yi Zhong, counselled business immigrants seeking permanent residency to provide residential addresses in P.E.I. though they didn't really live there.

"The 566 clients associated to the two addresses ... are well beyond what would be expected for a single dwelling residence and motel," investigator Lana Hicks said in one warrant.

The nine thick search warrants tell the story of how the probe began on March 30th, 2015, when a border officer red-flagged the watch.

Soon, Hicks, an 18-year veteran of the border service, was searching for two witnesses in a potential watch-smuggling case.

One man had provided 281 Brackley Point Road in Charlottetown as his address.

When Hicks called, she found a hotel reception desk, and decided to run a check through the agency's case management system.

It turned out to be the Sherwood Inn and Motel, not far from the airport's entrance.

A computer search showed 363 immigrants entering Canada under the province's business immigration program had used the motel as a "mailing and/or residential address" to federal agencies.

Hicks wrote that she decided to open "a spin off" file to see what was going on.

She then found from further database checks that 205 immigrants used 27 Beach Grove Road, the home of hotel owner Ping Zhong, as their mailing or residential address.

By now, "case number V0184978C" was in full swing, as it probed the inner workings of the provincial nominee program, known as the PNP, in which the provincial government recommends potential immigrants to the federal government.

The investigators started setting up surveillance teams.

They watched the travel plans and lives of various Chinese immigrants under the nominee program, documenting how they claimed the motel as an address while other records indicated they were living in places such as Vancouver or Toronto.

"Her permanent residency card would have been mailed to (the hotel) and I believe that it would have been received at the hotel and re-mailed to the client in Ontario," Hicks wrote.

In September of 2015, the search warrants say a team of three investigators conducted surveillance at the Charlottetown airport as a Chinese woman and her family arrived and were greeted at the airport.

They watched as the family went to the Delta hotel downtown, stayed there for a few nights, were taken for their interviews with the P.E.I. Office of Immigration, stopped at the Sherwood for a few minutes, and then flew out of the city.

In checks with Canada Post, the investigators say they found mail -- including key immigration documents -- being sent to the Sherwood or Ping Zhong's residence wasn't being redirected.

The investigators said they observed a person passing mail directly to a Canada Post van outside the hotel, and say they regarded this as suspicious.

Reached via cellphone this week, Ping Zhong, 60, declined to comment and said she and her 58-year-old brother have hired a defence lawyer. They will appear in court next month.

The Canada Border Services Agency alleges the siblings "aided and abetted" the misrepresentations by seven immigrants. However, the year-long effort of covert surveillance also claims 566 immigrants in the provincial nominee program submitted the same two addresses as their principal residence to Ottawa between 2008 and 2015.

In one search warrant application, urging the judge to allow a search of the Sherwood in February of 2016, Hicks argued that residency fraud hurts the integrity of the Canadian immigration system.

Jamie Aiken, the executive director of P.E.I. Office of Immigration, said in an interview Wednesday that he's yet to receive the list of 566 immigrants from CBSA, but that his office's records currently only show 17 cases where the immigrants had the Sherwood motel or Ping's home as their residence.

He said in the other cases, it appears the business immigrants provided the province with another address on the Island. However, he doesn't know yet how many of those left or ended up dropping out of the program.

"The claims the CBSA have filed with the courts are concerning," he said. "We want to work collaboratively with regulatory bodies with regards to this."

"We need to continue monitoring this."

The arraignment of the Zhongs is set for June 11 at Charlottetown provincial court.

The PNP program has long been a topic of debate and controversy in P.E.I.

Several Canadian immigration lawyers have argued the program is flawed because it grants permanent residency before there's proof the immigrants have actually stayed on the Island and created a business for a year.

Instead, the system nominates would-be immigrants for permanent residency, and the coveted status is awarded after federal vetting for health and security.

The immigrants do stand to forfeit a $150,000 escrow deposit, a price many are apparently willing to pay.

Last year over half of all the 269 applicants forfeited their deposit and never opened a business, raising $18 million for the small province.