Speaking over a scratchy telephone line from inside a Cuban prison, Sarkis Yacoubian’s voice goes suddenly silent. He’s crying.

“I was so depressed at times, I wanted to commit suicide,” says the 53-year-old entrepreneur.

In exclusive interviews from the La Condesa prison, Yacoubian provides an insider’s view of a sweeping anti-corruption campaign by the government of Raúl Castro that has seen several foreign businessmen — including himself and another Toronto-area businessman — jailed.

A joint investigation by The Toronto Star and El Nuevo Herald has found that in a corruption-plagued country described in secret U.S. government cables as “a state on the take,” the two jailed Canadians are embroiled in a high-stakes diplomatic and legal stand-off between Havana and Ottawa, potentially jeopardizing millions in taxpayer dollars that underwrite Canada’s trade with Cuba.

Arrested in July 2011 and detained for nearly two years without charges, Yacoubian, who ran a transport and trading company, was finally handed a 63-page indictment last month accusing him of bribery, tax evasion and “activities damaging to the economy.”

A suspect who says he quickly pointed the finger at widespread wrongdoing by other Canadian and foreign businesses, Yacoubian now faces up to 12 years in prison after he pleads guilty at his trial set to begin next Thursday. The charges were filed in a special Havana court for Crimes against the Security of the State, which can effectively hold trials in secret.

“They found out this was an epidemic going all over the place and I was the fall guy,” says Yacoubian. “They want to give an example to the rest of the businessmen. They want to scare them to death.”

The second Canadian — 73-year-old Cy Tokmakjian who runs a global transportation firm called the Tokmakjian Group — was picked up by Cuban authorities in September 2011 and remains in jail with no specific charges filed against him.

“We’re as worried as anyone would be if their father is in a place where they shouldn’t be,” said his son and company president Raffi Tokmakjian in an interview at their corporate headquarters in Concord, Ontario.

Raffi and his two sisters say they are in daily phone contact with their father. “He worries more about us. He says: ‘You guys stay strong, I’m okay,’” said Anni Tokmakjian, the company’s director of sales. “We’re just focusing on getting him home, that’s all we really care about.”

But that might not be easy. The two entrepreneurs of Armenian origin, one-time business associates turned bitter rivals, ran multi-million dollar trading companies that sold heavy equipment, vehicles and supplies to Cuban state companies in the transport, construction, nickel and other industries.

Today, their Havana offices are shuttered, their fortunes frozen and their future in limbo.

Cuban authorities in Havana and at the country’s embassy in Ottawa declined to be interviewed for this story.

Complicating matters is that millions in Canadian taxpayer dollars funded by the Canadian Commercial Corporation (CCC) — a kind of broker that underwrites contracts between the Cuban government and select Canadian firms — may be at stake.

In 2011 and 2012, the CCC signed 38 contracts in Cuba worth more than $68.4 million, the latest in its $650-million business with Cuba since 1991. Much of that financial support — for privacy reasons, the agency won’t disclose its client list — went to back deals made with the Tokmakjian Group.