At 1515 central time, a Cessna 150 crashed while chasing a bank robber near Trenton. The pilot was seriously injured and the passenger was not injured. The pilot was assisting the local police in tracking a bank robber. During the observation flight, the robber was tracked to an open field near the airport. The pilot entered a steep turn in an effort to corral the bank robber into a confined area until ground personnel were on site. As the pilot continued the maneuver, he encountered a wind gust and was unable to recover before the airplane collided with the ground.