By CBS3 Staff

PHILADELPHIA (CBS) – Philadelphia police are investigating a deadly home invasion in Mayfair. Police say two men, impersonating police officers, broke into an apartment but it was the resident who started shooting.

Police say the victim’s instincts may have just saved his life.

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The home invasion happened at Battersby Street duplex. It was no doubt a terrifying situation, but the victim fought back.

One of the robbers is now dead. The other suspect is still at large.

A home invasion victim turned the tables on two robbers who threatened him with a gun, pulling out his own gun and killing one of the suspects.

“I was in my bedroom and then I heard the gunshots. I heard pow, and then a second or two, and then pow, pow, pow, pow, pow,” said Steven Schaefer, the victim’s neighbor.

It happened on Battersby Street in Philadelphia’s Mayfair neighborhood around 10 o’clock Sunday night.

Police say a 25-year-old man was coming home when two men pretending to be police walked up and forced him into his apartment. Once inside, the robbers zip-tied the victim’s hands behind his back.

Police say at this point, the victim realized the robbers were not actual police officers. While still zip-tied, the victim was able to get hold of his gun and shot one of the suspects three times.

The robber collapsed with gunshot wounds to his head, chest and arm. The other robber ran away.

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When officers arrived on scene, the victim was still zip-tied.

“The ambulance was here. They did carry a person out,” Schaefer said.

Paramedics rushed the wounded robber to Jefferson Torresdale Hospital, where he was pronounced dead.

Police say the suspect was in possession of a police badge and more zip-ties.

The incident has neighbors concerned about their safety.

“Northeast Philadelphia has been a relatively peaceful part of the neighborhood, but it seems like things are getting worse,” Schaefer said.

Police say the victim had a license to carry and is cooperating with the investigation.

Police say they’re interviewing a woman who was on the second floor because she’s a potential witness to the crime.

Police are still searching for the second suspect.

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CBS3’s Wakisha Bailey and Madeleine Wright contributed to this report.