Police uncovered a gun trafficking ring after making a third arrest in connection with a fatal home invasion in Lower Merion, Pennsylvania.

Authorities say a Pennsylvania man was murdered when two members of a gun trafficking operation went to the wrong house in an effort to steal guns from an elderly couple who had been hired by the junk removal company they worked for.

Another man has been charged with murder and conspiracy in last month’s deadly home invasion in Lower Merion. According to the Montgomery County District Attorney’s Office, it was all part of a larger gun trafficking ring.