Johannesburg (AP) — Police in South Africa on Wednesday said they had arrested 11 people, including many suspected of being illegal miners, and were seeking a potential connection to Sunday’s shooting at a pub that killed 10 people.

In search for illegal miners in the area, police and Sibanye-Stillwater mine security stormed two houses in Westonaria, 46 kilometers (39 miles) outside Johannesburg. Nine citizens of Lesotho and one Mozambican, thought to be living in South Africa illegally, were among those arrested. Police said they were found with unlicensed firearms, including four handguns and an AK-47 rifle.

Maj. Gen. Fred Kekana, acting provincial commissioner of Gauteng, told reporters that police had found cartridges and live ammunition of the “same type” of firearms at the shooting scene in Bekkersdal. They were sent for testing to determine if they were used in the shooting.

Authorities also arrested a South African mine employee who faces charges related to harboring tenants living in the country illegally and potentially defeating the ends of justice. On Tuesday, the pub’s owner was charged with fraud and operating an illegal liquor outlet.

Surrounded by abandoned mine shafts, townships west of Johannesburg like Bekkersdal are notorious for illicit mining operations, which have led to problems including gang violence and the proliferation of illegal firearms.

Sibanye-Stillwater operates several significant operations in the region.

In areas where the mining industry once thrived, illegal miners known as “zama-zamas” have continued to operate. The trade is believed to be predominantly controlled by migrants who illegally enter from Lesotho, Zimbabwe, and Mozambique.