Fifteen people were sentenced by two courts in Changsha, Hunan province, on Thursday for their involvement in a building collapse that killed 54 people in 2022.

Wu Zhiyong, the owner of the building, was sentenced by the courts to 11 years in prison. The courts found that he had added extra units to the original building that he leased to restaurants and accommodations without legal permits.

The building collapsed on April 29, 2022, in the Wangcheng district of Changsha, killing 54 people and injuring nine others.

Wu also did not make any effective rectifications after noticing significant hazards in the building, and he did not evacuate people in the building after clear signs of the impending collapse, causing not only major casualties, but also economic losses. He also deliberately damaged other people's properties multiple times, the courts said.

The verdict was announced by Changsha's Wangcheng district people's court and the Ningxiang city people's court on Thursday.

The courts found Wu guilty of two crimes — causing a major accident, and provocation and disturbance.

The designer of the building and two others who added the units have been sentenced to up to six-and-a-half years in prison. None of them was qualified to perform the duties.

The company that provided blueprints for the units was fined 1 million yuan ($14,000) by the courts, and six people who worked on the blueprints were fined and sentenced to between two years and nine months and four years and nine months in prison. They have also been banned from working in the construction industry for life.

Zhou Zhengmao, former deputy head of Wangcheng district, was sentenced to 12 years in prison and was given a fine for dereliction of his duties and taking bribes.

Four other former district and provincial officials were also sentenced for dereliction of their duties. They received sentences of between three years and nine months and five years and six months in prison.

The courts handed down the sentences based on facts, damages and whether the suspects admitted to their crimes.

According to an investigation report issued last year by the State Council, China's Cabinet, the incident resulted directly from illegal construction. The report determined that the illegally built five-story building, which was later extended to eight stories, was of poor quality and could not support itself after the extension.

The report also noted that some authorities at the provincial, city and district levels of government were sluggish in rectifying illegal construction incidents, failed to conduct daily inspections and were negligent in punishing unlawful behavior.

Four officials supervised by the Communist Party of China Central Committee were held accountable for dereliction of their duties, and 62 public servants were punished for violating Party disciplines and national laws in the incident, the report said.

Xinhua contributed to this story.