DURHAM (WTVD) -- A Durham police officer admitted under oath that he lied in order to gain entry to a home and to serve an outstanding warrant.During a court hearing last May, court officials say he told a District Court judge that it was a common practice within Durham's police department.He said he knocked on a resident's door, claiming police had received a 9-1-1 hang up call. But, it never happened.It's the reason why Durham Police Chief Jose Lopez sent out an internal memo obtained by ABC11."Effective immediately," Lopez wrote, "No officer shall inform a citizen that there has been a call to the emergency communications center, including a hang up call, when there in fact has been no such call."ABC11 spoke with Chief Lopez by phone while he attended an FBI Training Institute in Washington D.C.Lopez denied the officer's claims that lying to get consent to enter a home is a common practice."This has never occurred," said Lopez. "We want to find out what...led him [the officer] to believe that this is something he should do."Lopez said his department immediately launched an internal investigation. If the officer's claims prove to be true, it would be a clear violation of department policy and in some legal circles, a violation of the Constitution.Lopez didn't rule out some form of discipline for officers found in violation of the department's policy. He also emphasized his staff is only aware of this single incident.Durham's City Manager Tom Bonfield is towing a tougher line, promising to look into the allegation."If confirmed that this tactic was used, the city manager agrees that it is entirely unacceptable," Bonfield said through a city spokesperson. "This tactic is not a policy, nor an acceptable practice of the department for any reason."