Beijing authorities have begun investigating a traditional Chinese medicine chain after learning its founder built an illegal house on top of a 26-story apartment building.

The Qijingtang TCM chain is being investigated by the Beijing Administration for Industry and Commerce's Chaoyang branch, a spokeswoman named Song said.

The authority will investigate the chain's licenses and release the results as soon as possible, Song said.

Zhang Biqing, the chain's founder, said he will demolish the illegal house within 15 days, as ordered by the authority, Mirror Evening News reported on Tuesday.

Haidian district chengguan, or urban patrol officers, issued a notice on Monday that Zhang should demolish the house within 15 days, as it was illegal.

The house, on top of a 26-story apartment building in the Renji Shanzhuang community, was built with rock and decorated with trees and bushes, covering more than 800 square meters.

Neighbors complained about the home as it was being built in 2007, and later about music and singing late at night after it was finished.

Zhang said he was aware of the problem and will demolish the illegal parts of the house, Mirror Evening News reported, but he dismissed allegations that he had beaten a neighbor who argued with him over the illegal building.

Zhang is a former member of a district branch of the Chinese People's Political Consultative Conference, the political advisory body, according to chengguan authorities.

His case became a hot topic among Chinese netizens, who also questioned his experience in curing diseases, which was mentioned on Qijingtang's website and the website of a medical research academy he headed.

According to its website, Qijingtang has 11 stores in Beijing and many others across the country.

"We have our own legal representative. The operation of this shop has nothing to do with Zhang," said a woman named Zhao, who is in charge of the Qijingtang chain store in the Hujialou area of Chaoyang district.

"We only introduce his therapy, but we have no contact with him now," Zhao said.

"Our massage therapists have all received formal medical training."

Zhao said the store uses magnetic acupuncture therapy to relieve pain in the cervical vertebra and omovertebral bone.

According to the State Administration of Traditional Chinese Medicine, the store has been approved for prostate disease therapy.

Healthcare products on the shelves of the store in Hujialou cost from several hundred yuan to more than 2,000 yuan ($327).

The store's reception hall covers about 10 sq m, with three rows of benches for waiting patients.

According to its website, Qijingtang has a training department, which charges 3,000 yuan for a course.

People who complete the course receive training and occupation qualification certificates for therapists, which say they have been approved by the Ministry of Human Resource and Social Security.

The website was closed on Tuesday afternoon for an upgrade, according to a Qijingtang employee.

The Chaoyang branch of the Beijing Administration for Industry and Commerce said it will investigate Qijingtang's training program.

Liu Yiran and Yan Ran

contributed to this story.