New Jersey law enforcement officials say that six schools in the state received fake threats Friday.

Linden High School was one of the schools threatened, according to officials. Students were told to shelter in place when a bomb threat was called in around 8:45 a.m.

Police searched the building, but found nothing. The school was declared safe around 11:15 a.m.

Linden Police Chief David Hart said in a statement, "It is unfortunate that our children's education has to be disrupted by reckless threats like these. Each of these threats are taken very seriously, and we will use every resource at our disposal to ensure that the person responsible is brought to justice."

Police in Lawrenceville say that three schools in the town also received threats. They called these threats a “swatting incident.”

Bomb threats were called in to Lawrenceville Prep and Ben Franklin Elementary School. A shooting was called in to Lawrenceville Elementary School. All threats turned out to be hoaxes.

Threats were also called in at County Prep High School and McNair Academic High School in Jersey City.

Officials say that they have not yet determined if the threats are all related.