Updated

Authorities have closed a popular North Carolina park after a runner impaled his foot on a nail that they believed was purposely placed.

Local media outlets report a search of the 1,100-acre Pinnacle Park in Jackson County, about 162 miles west of Charlotte, has turned up 40 nails hammered into tree roots and logs since Saturday.

Brian Barwatt, an engineer with the N.C. Department of Transportation and the director of a trail race in Pinnacle Park in March, said someone hammered 4-inch long galvanized nails and left them sticking out one-half to 1 inch, and at an angle. One person was hurt and another stepped on a nail that went through his shoe but didn't hurt his foot.

There is a $1,000 reward for information leading to the arrest and conviction of those responsible.