Mingxing “Star” Xu, founder of OKCoin and CEO of OK Group, has resurfaced after being detained by Chinese police.

According to a report by Bloomberg Thursday, Xu appeared on a private social media platform to post that he had been cooperating with an investigation relating to an equity merger that OK Group had finalized years prior.

The equity investee was the target of a "complicated" legal case, Xu said, choosing not to go into further detail. It remains unclear as to precisely to which deal he was referring.

“The authorities have clarified the matter and proved me innocent,” Xu wrote Friday on his WeChat feed, per Bloomberg's reporting. “In coming days I’ll call on everyone who supported OK Group to express my gratitude.”

As CoinDesk reported, the related Malta-based exchange OKEx was forced to suspend all account withdrawals on Oct. 16, it said, because an unnamed holder of the keys to the crypto assets had been detained. A report in Chinese newspaper Ciaxin said the key holder was Xu, based on sources "close to" the company.

Xu's temporary detention and subsequent release closely coincides with the period the mystery key holder also became unavailable. The exchange said Thursday it would restart withdrawals by next Friday because the key holder had been released from "assisting the authorities" and "has now returned to his normal business functions."

OKEx has previously told CoinDesk that Xu has no direct relationship with the exchange. We reached out to OKEx again on Friday to gain clarity on Xu's relationship and why he may be holding the keys if, as the facts suggest, that is the case.

"OKEx has been a separate entity from OK Group from 2017. Star therefore has not been in any kind of operation in OKEx. In the interests of user security, OKEx maintains all details about private key holders confidential, as such, we are unable to comment on this neither can we provide any comment on Star Xu," a representative reiterated.

See also: OKEx Token Rallies on Rumors Founder Xu Released From Custody

The exchange said in its announcement that it is preparing to allow "unrestricted withdrawals" by Nov. 27.

The withdrawals news has helped the exchange's OKB token recover from a slump over the last month. OKB is now trading at $5.88, up around 23% since Wednesday.