Xavier Andre Justo plans to appeal his three-year jail sentence, The Straits Times reported today.

In an exclusive interview with the Singapore paper, the Swiss national, who was on Aug 17convicted of blackmailing his former employer, PetroSaudi International, said the three-year jail term meted out on the same day came as a surprise.

"I wasn't expecting three years," he told the paper. Speaking in the presence of his Swiss lawyer Marc Henzelin from Bangkok’s Klong Prem prison, where he is serving his sentence, Justo said he expected a lighter sentence, seeing that he had given a full confession and had fully cooperated with the police.

Justo said he was currently looking for a new Thai lawyer before his Sept 17 deadline to file an appeal is up.

Justo had stole data from PetroSaudi, which contained details of a deal between them and 1Malaysia Development Berhad (1MDB). He had quit the Saudi-based energy firm in 2011.

In 2013, Justo had demanded 2.5 million Swiss francs (about RM10.9 million) from PetroSaudi's chief executive for not giving out details he had on the company. PetroSaudi filed a report with the Thai police in May this year.

Justo was arrested at his home in Koh Samui in June.

The 49-year-old claimed ignorance to the content of the files that he stole.

"I am not a whistle-blower," Justo told The Straits Times. "It would be easy to be seen in that image, but I am not. They (the buyers) had a political agenda that I didn't know (about). I had no idea what was in those files. I didn't know they were trying to bring down a government. I was stupid," the paper quoted him as saying.

In a July 23 exclusive, The Straits Times reported that Justo had revealed he was promised US$2 million (around RM8.4 million) for the stolen data by The Edge Media Group owner, Tong Kooi Ong. Justo claimed he was never paid.

He also claimed that those he had previously met, including Sarawak Report editor Clare Rewcastle-Brown, had talked about plans to "modify" the data and use the data "to try to bring down the Malaysian government".

Tong, in a joint statement with The Edge Group publisher Ho Kay Tat in July, had noted that they had misled Justo, but claimed "that was the only way to get hold of the evidence to expose how a small group of Malaysians and foreigners cheated the people of Malaysia of US$1.83 billion."

They had also denied modifying the data.

The Edge Malaysia and The Edge Financial Daily were subsequently suspended by the Home Ministry for three months from July 27.

Meanwhile, Justo claimed he has not been contacted by anyone from Malaysia.