Police detained eight suspects over a fire that damaged the 99-year-old Tsinghua Schoolhouse in Beijing, and the university will be punished for poor supervision.

The Fire Bureau of the Beijing Municipal Public Security Bureau has ruled out arson and fireworks, but is still collecting evidence to determine the specific cause of the accident, the bureau announced at a press conference on Friday. The bureau put losses at over 180,000 yuan ($27,110.47).

"We learned the preliminary investigation results about the fire from the media, but haven't received any written reports so far," the Tsinghua University press center told the Global Times Sunday in a statement.

There were no eyewitnesses or surveillance videos, making it difficult to collect evidence, fire bureau official Wen Jun said at the press conference.

The eight suspects obstructed the investigation by giving false testimony, the inquiry found. Project managers from the No.3 Construction Company, which was contracted to renovate the Tsinghua Schoolhouse, allegedly ordered the construction workers to lie.

The workers previously told police that they had stopped construction by 5 pm on November 12, and didn't use open flames for their work. They also claimed no one was living on the site. But police later found that six workers were living on the site and were waterproofing until a few hours before the fire broke out, and that they used open flames, according to the fire bureau.

The two-story Tsinghua Schoolhouse, a national cultural relic built in 1911, caught fire at around 1 am on November 13. No injuries were reported.