Four of the almost 50 elite law firms targeted by a Russian hacker were from Chicago, it was reported in an alert from Flashpoint, a New York-based computer-threat intelligence company.

The firms were Kirkland & Ellis, Sidley Austin, McDermott Will & Emery and Jenner & Block; all listed on a spreadsheet of potential targets of a cyber break-in into the company’s computer systems.

The leader of the threat is a broker named “Oleras,” living in Ukraine. He has been trying to gain access since January into these law firms’ computer systems by means of hiring hackers. His wish is to find information which will then allow him to trade using insider information.

Flashpoint notified law agencies, but would not comment any further. As of March 4th the FBI has the illegal activity under investigation.