TAIYUAN, Dec. 31 -- Two more police officers were arrested in north China's Shanxi Province for beating a migrant worker to death, local authorities confirmed on Wednesday.

The two suspected officers, surnamed Guo and Ren, were arrested for allegedly abusing their power, according to a statement on the official website of the People's Procuratorate of Taiyuan, Shanxi's capital.

Previous investigation showed that on December 13, more than ten migrant workers were trying to enter a construction site. The guards stopped them at the excuse that they were not wearing safety helmets.

A quarrel later developed into a brawl when police arrived. A 47-year-old female migrant worker Zhou Xiuyun died in the incident.

A policeman surnamed Wang was arrested earlier for allegedly causing Zhou's "unnatural death".

According to an earlier report, Zhou's husband's ribs were broken by police in the dispute. Guo and Ren are suspected to be responsible for the injuries.

The case has drawn criticism in China, after a picture supposedly showing a policeman stepping on the hair of Zhou as she lay on the ground motionlessly, circulated widely on microblog Sina Weibo.

Zhou's son told Xinhua that 13 people from his hometown have worked at a construction site in Taiyuan since mid-October. But the boss delayed payment of their 29,000 yuan (about 4,700 U.S. dollars) salary.

They planned to ask for their money and return home to celebrate the upcoming Spring Festival, or Chinese New Year, he said.

"Police officers are part of a nation's image," said an internet user nicknamed Fanghouyuan. "Should such things happen in a country which is governed under the rule of law?" Many others cried for severe punishment of the culprits.

The local procuratorate set up a special team to investigate the case. They are negotiating with Zhou's family to perform an autopsy to determine the exact cause of her death.