DOVER – Central Middle School and three other schools throughout the state were placed on lockdown this morning after threats.  The lockdown at the Dover school was lifted after less than an hour of being initiated.

Meanwhile, Long Neck Elementary School in Millsboro, Woodbridge High School in Greenwood and Silverlake Elementary School in Middletown each received threats, Delaware State Police spokesman Master Cpl. Gary Fournier said.

Meanwhile, Dover Police Department responded to Central Middle School after an automated call similar to last week's automated bomb threats, according to Dover police spokesman Master Cpl. Mark Hoffman. Central Middle School said there were reports of possible shooters on the roof.

Central Middle School (Delaware State News/Dave Chambers)

Central Middle School was placed on lockdown, and Dover police responded around 9:30, about a minute after being contacted by the school resource officer.

State and local police units arrived at the other schools around the same time.

In Dover, officers cleared the school, and according to Central Middle School, Dover police said at 10:20 the lockdown could be lifted.

Dover police reported more calls are taking place at other schools in the area.

Police continue to investigate, and anyone with information is asked to call Dover Police Department 736-711 or to Delaware State Police.

State police can be reached at Troop 2 Youth Aid Division at 834-2620, Troop 3 Youth Aid Division at 697-4454 or Troop 4 Youth Aid Division at 856-5850.  Information may also be provided by calling Delaware Crime Stoppers at 1-800-TIP-3333, going to www.delaware.crimestoppersweb.com or sending an anonymous tip by text to 274637 (CRIMES) using the keyword "DSP."