The Justice Department posted a $20,000 reward Monday for information about the person who has shot at the Pentagon and several other military-related buildings in Washington's Virginia suburbs.

No one has been injured in the five shooting incidents, all of which came during overnight hours.

The FBI's Washington field office announced the reward for material that leads to an arrest and conviction.

The shooter first took aim at the National Museum of the Marine Corps in Triangle, Va., in mid-October. A few days later, the gunman fired several shots at the Pentagon.

Later incidents occurred at a Marine Corps recruiting station in Chantilly, Va. and then again at the museum, which is associated with the Quantico Marine Base, 30 miles south of the Pentagon.

The last shooting was reported Nov. 2 at a Coast Guard recruiting office in a suburban strip mall.

Authorities have said they don't believe the shooter wants to hurt anyone. John Perren, acting assistant director for the FBI field office, said last month the shooter may have a problem with the institution of the Marine Corps.

Ballistics tests have linked all five shootings to a single gun. Officials initially said it appeared to be a rifle, but they have not released any details about the type or caliber of weapon.