( CNN ) -- Four people died after a small plane crashed into a building near Wichita 's Mid-Continent Airport in southern Kansas on Thursday morning , city Fire Marshal Brad Crisp said . While five people were initially transported to the hospital , three of those patients were reportedly treated and released . `` Firefighters engaged in a horrific fight for several minutes . We have the fire under control . We are in the process of trying to determine if all the employees and visitors who may have been in the building are accounted for , '' Fire Chief Ron Blackwell told CNN affiliate KSNW . About 50 to 60 firefighters responded and were evacuated after the structure was deemed unstable , Wichita police said . Two of those killed were inside the building when the plane crashed , police said . The pilot was killed , CNN affiliates reported . One of the injured was in serious condition and another in fair condition , an official with Via Christi Health , a local hospital , told KSNW . The other three , who were in good condition earlier in the day , were released , the station reported . FAA and National Transportation Safety Board investigators are on the scene . `` There is a small aircraft that went into the FlightSafety building '' near Mid-Continent Airport , said Steve Phillips , a FlightSafety International spokesman . The plane was a Hawker Beechcraft B200 Super King Air , Phillips said . It was en route to Mena , Arkansas , CNN affiliate KWCH reported . The FAA said the twin-engine plane lost an engine on takeoff and crashed into a two-story building , KSNW reported . The roof on the building 's eastern side has collapsed , the station reported . No information has yet been released on the identities of those in the plane or in the building . According to one aviation website , the aircraft can carry as many as 13 passengers . It `` crashed into the roof of our training center . I have no information on how many on board , '' Phillips said . `` We have the manager of the training center on site , and he 's making sure everyone is OK , but I do n't have an answer for that . '' The building is across the street from the airport , he said . There were about 100 people inside the building at the time , Blackwell told KWCH . Video from KSNW showed thick smoke rising from the building at 10:20 a.m. ( 11:20 a.m . ET ) . Flights were operating normally , though some roads around the airport were blocked off , the airport said in a tweet . `` The building has sustained serious damage , including the collapse of walls and ceilings , '' read another airport tweet . CNN 's Jason Hanna and Amanda Watts contributed to this report .
Pilot was among victims ; two of the dead were on the ground . Official : " The plane crashed into a mountain and exploded, killing everyone onboard except for one person who jumped out before it hit the ground. " Part of building 's roof collapses .