The Chaoyang Public Security Bureau announced the development in its probe on its WeChat account. It launched its investigation in November.

Such measures could include putting suspects under residential surveillance, detention or arrest.

Zhongzhi did not immediately respond to a request for comment.

Zhongzhi filed for bankruptcy liquidation in January after failing to repay debt. It apologised to investors in a letter last year that said it was heavily insolvent with up to $64 billion in liabilities.

The company was a major player in China's $3 trillion shadow banking sector - roughly the size of the French economy - and its woes added to worries that the country's property debt crisis was spilling over into the broader financial sector.

(Reporting by Brenda Goh; Editing by Stephen Coates)