Man, possibly armed with knife, barricaded inside Langley Park home Posted at 01:04 PM ET, 02/06/2013 A man possibly armed with a knife has barricaded himself inside a home in the Langley Park area, and Prince George's County police officers have been trying for more than 10 hours to talk him out peacefully, authorities said. Those officers are still outside the home in the 8500 block of 14th Place, said Lt. William Alexander, a Prince George's County police spokesman. He said they believe the man is alone inside. The incident began just before 1:20 a.m., when the man called 911 and seemed mentally unstable to dispatchers who answered the phone, Alexander said. He said officers went to the man's house to investigate what was wrong and saw him inside, possibly armed with a knife or other edged weapon. Police declared a barricade situation and have been working ever since to coax the man outside, Alexander said. It remains unclear what precisely is upsetting him.