CBS said it has expanded its anti-takeover lawsuit.

The network said the suit against Fairness in Media, an advocacy group threatening to buy the network, was expanded to include National Congressional Club, Jefferson Marketing Inc. and Educational Support Foundation--all entities controlled by members of Fairness in Media. The complaint charges the defendants with violating federal securities laws, improper political activities by tax-exempt organizations and illegal corporate political contributions. Fairness in Media is threatening a proxy fight against CBS because of what it claims is a liberal bias in the network’s news coverage.