"It's a very said day for justice in East Timor," Ramos Horta said in a message sent to Lusa. "I still believe that the appeal court will restore justice."
The former president - who has attended several of the sessions at the Dili courthouse - had in the past publicly commented on the case, which has also been followed closely by Portuguese and other foreign diplomats in the country.
In a post on social media last week, Ramos Horta said that the Guerras - who for the last three years have been prevented from leaving East Timor, while their two children have been living in Portugal with Tiago Guerra's parents - had already suffered too much in this case, and expressed the hope that they would be found innocent.
But on Thursday the panel of judges at the Dili district court found the couple guilty and sentenced them to eight years in prison for embezzlement, ordering them to pay the state $859,000 - the amount they supposedly embezzled. The court found them not guilty of two other charges: money laundering and forgery.
"The accused damaged the finances and the economy ... and defrauded the state of Timor," the presiding judge said. "They acted freely, deliberately and consciously, knowing that their conduct was not allowed in law and that they were criminally punishable."
In a message emailed to Lusa, the couple said they were "shocked" by the verdict, in a case that they described as a "lie" that had already stolen three years of their lives and those of their children, as well as "the confidence of the people who love" East Timor.
"We have nothing to return to East Timor," they wrote. "Because we stole nothing, we do not have nor have we have had in our possession any sum nor anything that belongs to Timor.
"Everything we have and have had is to the court's knowledge, proven by documents issued by the relevant entities and authorities."
Public prosecutors had requested eight-year prison sentences for the couple, while the defence had requested that they be cleared. The defence has already appealed the verdict, arguing that it is "full of contradictions".
The case centres around a sum of $859,000 that was transferred by the couple in 2011 at the request of Bobby Boye, a US consultant paid by the government of Norway and then of East Timor and who was at one point also accused in the same trial. The couple have said they were "tricked and used" by Boye, like the two governments.