Embattled Chinese conglomerate HNA Group said Friday that its chairman Chen Feng and Chief Executive Adam Tan are suspected of committing crimes and have been detained.

HNA said on its official social media account that the pair were “placed under compulsory measures,” citing a notice from the Hainan police. It added that the company’s operations remain orderly. HNA has been under a court-led bankruptcy and reorganization proceeding since January.

HNA,...

Embattled Chinese conglomerate HNA Group said Friday that its chairman Chen Feng and Chief Executive Adam Tan are suspected of committing crimes and have been detained.

HNA said on its official social media account that the pair were “placed under compulsory measures,” citing a notice from the Hainan police. It added that the company’s operations remain orderly. HNA has been under a court-led bankruptcy and reorganization proceeding since January.

HNA, based in the southern island-province Hainan, used to be one of China’s most acquisitive companies. It aggressively scooped up trophy assets around the world from 2015 to 2017, buying stakes in the Hilton hotel chain, Deutsche Bank AG and high-end commercial real estate in more than $40 billion worth of deals.

The shopping spree saddled the company with debt. HNA subsequently reversed course and sold many of its overseas assets, after Chinese regulators began scrutinizing its activities and banks and investors became less willing to lend money to the group.

In July 2018, HNA’s co-founder and then-chairman Wang Jian fell off a wall while sightseeing in France, and died at the age of 57. After the incident, Messrs. Chen and Tan took on bigger roles running the company.

The coronavirus pandemic battered HNA’s operations last year, especially its core airline businesses, which was hit particularly hard by lockdowns and travel restrictions in China.

In February 2020, the group was effectively taken over by the Hainan government. A government working group was sent to take control of HNA’s board and help the company devise a plan to overcome its liquidity problems.

HNA and its 320 subsidiaries were placed under a court-led reorganization early this year following petitions from creditors. Various HNA business lines, including its airlines and airport divisions, have been looking for strategic investors.

Earlier this month, Hainan Airlines Co. Ltd., the group’s crown jewel, said it planned to bring in Liaoning Fangda Group Industrial as a strategic investor. Liaoning Fangda, a privately owned conglomerate with businesses spanning carbon, steel, manufacturing and pharmaceuticals, will become the carrier’s controlling shareholder after the transaction.

The reorganization has also shed light on how HNA fueled its expansion with aggressive borrowing and financial engineering. The provincial government working group found that money was moved around within a sprawling web of more than 2,000 HNA subsidiaries, affiliates and shell companies, while billions of dollars were misappropriated.

Mr. Chen co-founded HNA with Mr. Wang, and turned what was originally a small regional Chinese airline into one of the country’s largest privately held conglomerates. Both men were formerly civil aviation officials. Mr. Tan joined the group in the early 1990s and oversaw much of its overseas expansion and acquisitions.

Write to Jing Yang at Jing.Yang@wsj.com