Some of the nine miners previously thought to have died in a shed explosion last week in Southwest China's Yunnan Province were killed by gunshots, local police said Monday.

Explosives at a shed at the Xiaosongdi Coal Mine were detonated at 9 am Thursday, when Zheng Chunyun, boss of the nearby Yuejing Coal Mine, arrived with more than 80 people armed with knives and steel bars.

Nine people were killed and 48 others injured in the incident. Most of the victims were with Zheng.

"Autopsies show some of them were gunned down before the blast," said Lu Qingwei, head of the public security bureau of Luxi county, where the mine is located.

Lu declined to give more details about the case.

The incident was apparently the result of a long-standing dispute between Zheng and Wang Jiangfu, the owner of the neighboring Xiaosongdi Coal Mine, who Zheng had accused of plundering his resources.

The local land and resource authority investigated last month and backed Zheng's accusations, according to Yunnan-based Shenghuo Xinbao.

It ordered Wang to stop operations in Zheng's mine and calculate the amount of coal his company had mined there, for which Wang reportedly had to pay tens of millions of yuan in compensation.

On November 18, Zheng and his staff went to Wang's coal mine to inspect the process as scheduled, when the explosion occurred and two of Zheng's men were gunned down, the paper reported citing witnesses.

Zheng and his staff had traveled in more than 10 cars and minibuses to the Xiaosongdi Coal Mine, said the report.

"The only thing we can confirm now is that the coal mine explosion was deliberately set off," a police officer surnamed Zhang from the Luxi Public Security Bureau told the Global Times Monday. Five people who were injured in the incident and were in critical condition are now stable.

The police have detained Wang Jianfu, boss of the Xiaosongdi Coal Mine, Zheng Chu-nyun and eight other suspects, Lu said.