Singapore police are investigating iron ore trader Radiant World after receiving reports about the company, according to a police spokesperson. Multiple outlets also report that police conducted a raid of the firm’s Singapore office last week and questioned some employees as part of the probe.

The investigation centers on concerns raised by business counterparties about Radiant World’s transactions, including allegations that documents used in dealings may have been falsified. Some major commodities traders have reportedly cut ties with Radiant World amid worries about the validity of invoices or other paperwork provided to banks.

While Singapore police confirm they are looking into the matter, outlets also describe additional parallel scrutiny. Free Malaysia Today reports that the probe is being conducted alongside an investigation by the US Department of Justice into transactions involving the firm, reflecting wider international interest in Radiant World’s business practices.