SILVER SPRING, Md. -- Montgomery County Fire Chief Richard Bowers says authorities have detonated an additional four devices linked to a gunman who took three hostages at the Discovery Communications headquarters.

Speaking at a news conference Thursday, Bowers said officials obtained the extra devices from a residence and successfully detonated them.

That's in addition to four devices that James J. Lee had brought with him during the hostage ordeal on Wednesday.

Bowers says investigators are still looking for a vehicle that was owned or operated by Lee.

Police Chief Thomas Manger says Lee was also carrying starter pistols, and not handguns as police had previously reported.

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