Police are seeking a man wearing a jacket with NASA logos who left signs with threatening messages outside a Pennsylvania mosque.

Maintenance workers at the Delaware County Islamic Center in Upper Darby found the signs on Monday. The largest sign read: "Wild dogs and boys of devils, get ready today."

Police Superintendent Michael Chitwood says "this guy ain't dealing with a straight deck" and he considers it a hate crime.

The man is described as 50 to 60 years of age, wearing a blue coat with a NASA logo, a red aviator or hunting style hat and blue jeans.