Firestone Diamonds plc confirmed in a statement to the media that police officers raided its Liqhobong mine in Lesotho on January 16.
The officers took away computer equipment, Firestone Diamonds said, even though they did not possess a search warrant or court order.
Firestone stressed, however, that operations had not been disrupted or impacted by the raid.
"The company has also confirmed that it is engaging with the Ministry of Police and has met with the Minister of Mines for Lesotho in order to understand the allegations behind the investigation," Firestone says. "The directors of Firestone are not aware of any wrongdoing by the company.
In addition to its Liqhobong mine in land-locked South Africa, Firestone is one of the largest holders of mineral rights in Botswana's diamondiferous kimberlite fields, controlling approximately 5,510 square kilometers including prospecting licenses around the Debswana-owned Orapa mine, as well as the entire Kokong and Tsabong kimberlite fields, and the BK11 operation.