CINCINNATI — A flawed demolition plan contributed to the collapse of a highway overpass that killed a construction worker in Cincinnati last month, the contractor for the construction project says.

The preliminary findings from an independent engineering firm have been sent to federal and state investigators, according to Kokosing Construction Company Inc.

“Our engineering firm has told us that it wouldn’t work the way it was,” Brian Burgett, chief executive officer of Columbus-based Kokosing, told The Cincinnati Enquirer.

The collapse during demolition work to remove an Interstate 75 ramp bridge just north of downtown Cincinnati killed Brandon Carl on Jan. 19. The parents of the 35-year-old father of four from Augusta, Kentucky, filed a lawsuit a week ago against Ohio’s Department of Transportation, charging negligence and carelessness.