A male inmate of the Webster County jail plunged about 40 feet from the roof of the building into the center of the alley on the structure's east side early Wednesday evening.
The man jumped from the fourth floor roof, a press release from the Webster County Sheriff's Department said.
Tanner Jon King, 21, of Fort Dodge, was taken to Trinity Region Medical Center and later transferred to a Des Moines-area hospital, according to the sheriff's office.
The extent of King's injuries had not been made public at press time.
He landed in the alley between Seventh and Eighth streets near First Avenue South between the Webster County Law Enforcement Center and the former Messenger Printing building around 6:30 p.m.
Investigators checked to see if King struck the former Messenger Printing building before landing in the alley, which is about 22 feet wide.
Webster County Sheriff's Lt. Kevin Kruse said he wasn't sure how the inmate got onto the roof.
"It's too early to tell," he said.
The recently renovated LEC has a rooftop exercise area.
Kruse said he would ask the Iowa Division of Criminal Investigation to handle the investigation.
"We need to have an outside agency handle it," Kruse said.
He said that is standard procedure.
Initial scanner calls regarding a possible diabetic reaction at the LEC quickly turned into a call for an inmate who had fallen off the roof.
The Fort Dodge Police, Webster County Sheriff's Department deputies and jail staff, Trinity Regional Medical Center paramedics and Fort Dodge Fire Department assisted at the scene.
The Iowa State Patrol assisted later in the evening during the ongoing investigation.