SPENCER, Iowa (AP) — Authorities say a northern Iowa high school evacuated after a bomb threat has been declared safe. The Spencer Police Department says students at Spencer High School were taken back to the school Wednesday afternoon then dismissed for the day.

The Sioux City Journal reports a written bomb threat was found Wednesday morning on one of the school’s interior walls. Officials say they took the threat seriously and transported students to an undisclosed location.

Officer Kyle Van Otterloo says officers checked around the school and found no explosive devices inside.