An environmental group is about to launch a substantial ad campaign against Rep. Marilyn Musgrave (R) in Colorado’s 4th district.

According to Federal Election Commission 48-hour notices, the Defenders of Wildlife Action Fund placed a $200,000 ad buy on June 19. The group also spent $11,794 on ad production to Wild Bunch Consulting. The exact content of the ad has not been released.

According to one Democratic insider, this could be a sign that environmental groups are targeting Musgrave’s defeat this cycle, as they did then-Rep. Richard Pombo (R-Calif.) in 2006.

The Defenders have already aired an ad against Rep. Steve Pearce (R) in New Mexico’s Senate race.