Jeffrey McGee, 32, of Schenectady, N.Y., was captured in Toronto, FBI spokesman Jay Spadafore said. He provided no further details of the arrest.
McGee is charged with murder in the death of Villa Rica Police Capt. Robbie Bishop, who was known for intercepting drug shipments on interstate highways.
Bishop, 35, was shot in the head Jan. 20 after stopping McGee on Interstate 20 in west Georgia. A copy of a warning ticket written to McGee was in Bishop's ticket book.
"We're all just happy" that McGee has been caught, said Robin Oehler, a secretary for the Villa Rica Police Department.
Bishop, an ex-Marine, hauled in a fortune in drug money and illegal drugs from drivers along Georgia interstates during a 12-year career. He also traveled to other states to teach his techniques to other police departments.
Authorities believe McGee boarded a flight to Los Angeles in Birmingham, Alabama, the day of the slaying. The plane made a stopover in Houston, but investigators said they were unsure where McGee was headed.
The Atlanta Journal-Constitution reported that McGee called his mother last week at her home in Schenectady.
"I asked him what happened, and he said, 'Ma, does it really make a difference what I got to say? They already got me convicted and hung,' or words to that effect," Vera McGee Lewis told the newspaper.
A reward of $55,000 had been posted for information leading to McGee's capture and conviction.