* PetroSaudi says it is not the target of the inquiry
* Fund at centre of laundering probes, denies wrongdoing
* Case in focus in build-up to Malaysian elections
ZURICH, May 1 (Reuters) - Swiss prosecutors said on Tuesday they were investigating two officials from Saudi energy group PetroSaudi as part of a wider inquiry into the suspected theft of assets from Malaysia's 1MDB state fund.
1MDB is at the centre of money-laundering probes in at least six countries, including Switzerland, the United States and Singapore. A total of $4.5 billion was misappropriated by high-level officials of the fund and their associates, according to civil lawsuits filed by the U.S. Justice Department.
The Swiss Attorney General's office said it had launched criminal investigations against two PetroSaudi officials in November 2017 "on suspicions of criminal mismanagement, fraud, bribery of foreign public officials, aggravated money laundering and misconduct in public office".
"One of the two suspects is also suspected of document forgery," it added without identifying either suspect. It said it had kept the inquiries under wraps to avoid jeopardising the investigation.
PetroSaudi, which ran an energy joint venture with 1MDB from 2009 to 2012, was not immediately available for comment.
The Financial Times, which first reported on the inquiries, cited the company as saying it was "aware of an ongoing investigation by the Swiss authorities related to 1MDB" but was not the subject of the probe.
The company told the Financial Times it rejected assertions that it or any of its officials were involved in the misappropriation of funds from 1MDB and would co-operate fully with authorities.
The new announcement threw the spotlight back on the case in the build up to Malaysian elections on May 9.
Malaysian Prime Minister Najib Razak, who set up 1Malaysia Development Berhad (1MDB) in 2009 and served as chairman of its advisory board, is seeking re-election. He and the fund have denied any wrongdoing.
Swiss prosecutors are also reviewing a criminal complaint filed against two former colleagues and an alleged accomplice by Xavier Justo, a former director of PetroSaudi International Ltd and a key figure in the 1MDB affair.
Justo has told Reuters he was trying to clear his name after being jailed in Thailand for blackmailing his former employer over its ties to scandal-hit 1MDB.
It was documents that Justo leaked after he left PetroSaudi in 2011 that triggered the international investigations into alleged theft of assets from 1MDB.
Reporting by Michael Shields Editing by Andrew Heavens