Malaysian police raided the Kuala Lumpur office of audit firm Deloitte on Thursday as part of a widening probe into a multibillion-dollar scandal at state fund 1MDB, two police sources told Reuters.
Investigators seized documents and records related to the firm's dealings with 1Malaysia Development Berhad (1MDB), one of the sources said.
A representative for Deloitte could not be immediately reached for comment.
Authorities in at least six countries are investigating alleged graft and money laundering at 1MDB, set up by former Malaysian Prime Minister Najib Razak in 2009.
Najib, who was ousted in an election last year, is facing dozens of criminal charges over losses at 1MDB and other state entities. He has consistently denied wrongdoing.
U.S. prosecutors say about $4.5 billion was misappropriated from 1MDB by high-level officials of the fund and their associates between 2009 and 2014.
Deloitte has been under scrutiny for its role in auditing 1MDB's financial statements in 2013 and 2014.
In January, Malaysia's securities regulator fined Deloitte 2.2 million ringgit ($524,746) for failing to report irregularities in relation to an Islamic bond issued by a 1MDB-linked company.
After the U.S. Justice Department filed civil lawsuits in 2016 over 1MDB, Deloitte said the 1MDB finance statements it had audited should no longer be relied upon.
Deloitte was 1MDB's third auditor after the fund fired its earlier auditors, KPMG and Ernst & Young, authorities have said.
It resigned as the fund's auditor in early 2016.