University police released a K-9 unit on a man they believed to be carrying a gun Thursday night, though no weapon was found, according to a police report. Police received a call just before midnight expressing concern about three men loitering in front of the Burger King on Washington Avenue. The caller said one of the men was carrying a chrome handgun in his pocket, according to the report. Upon arrival, University police pointed their weapons at Clarence Wilson, 21, who fled the scene, according to the report. After a brief pursuit, the police released a K-9 unit. The dog took down Wilson near Harvard Market on Washington Avenue and police arrested him. Police searched Wilson and the surrounding area, but did not find a weapon. He was charged with obstruction of justice and fleeing police. Wilson sustained minor injuries during the apprehension, including a small dog bite under his armpit and a scrape on his forehead, according to the report. Wilson could not be reached for comment. University Police Chief Greg Hestness said the use of a K-9 unit to pursue a suspect is not common, but he said the officersâÄô reaction was appropriate. âÄúThe K-9 handler is authorized to use his dog for an apprehension of somebody who might pose a serious threat to the officer or the public,âÄù Hestness said. âÄúCertainly somebody armed with a gun would meet that category.âÄù The description of the suspect was very specific. The 911 caller said the man was wearing a fur coat with a hooded sweatshirt. For that reason, Hestness said, it was unlikely that officers had mistaken the suspect.