The U.S. Securities and Exchange Commission has frozen the assets of traders it believes were involved in an insider trading scheme that made $3.6 million in illegal profits related to the recent takeover of Fortress Investment Group by Japan’s SoftBank Group.

A New Jersey judge granted the SEC’s request for an emergency court order freezing the proceeds of what the commission called “highly suspicious transactions within days of the public announcement” of the $3.3 billion Fortress takeover.

In a civil securities fraud complaint, the SEC said some of the traders were customers of Maybank Kim Eng Securities, a Singapore-based broker-dealer, and others were customers of R.J. O’Brien Ltd., a broker-dealer based in the U.K.

The traders “were in possession of material nonpublic information about the impending acquisition when they purchased Fortress [securities] in the days leading up to the public announcement” of the takeover, the SEC said.

The $8.08-a-share deal was announced after the U.S. markets closed on Feb. 14. According to the SEC, the deal was in serious doubt as late as Feb. 12 and it wasn’t until Fortress’s board received an email at 11:02 a.m. on Feb. 14 that included draft resolutions approving the transaction.

The Maybank customers allegedly began buying Fortress shares less than 25 minutes later at prices ranging from $5.92 to $6.35 a share and, after holding them for less than 24 hours, sold them for a profit of more than $1.6 million.

The trading of the R.J. O’Brien customers was also “very suspicious,” the SEC said, noting that they began purchasing Fortress-based “contracts for difference” on Feb. 10 and acquired additional CFDs at 9:33 a.m. on Feb. 14.

After the takeover was announced, Fortress shares jumped more than 28% on Feb. 15, closing just short of the deal price at $7.99.

The asset freeze will prevent any illicit profits from being removed from the traders’ accounts while the SEC’s investigation continues.