The Queens landlord suspected of killing his tenant was nabbed in Maryland after his license plate was flagged, sources said tonight.

Keith Howard, 63, was linked to the death of Karla Shah-Boguwalski, 39, after her body was found fatally stabbed in his apartment on Seaspray Avenue in Arverne on Oct. 2, cops said.

The license plate on Howard’s 2003 Acura was put out to law-enforcement and when a reader scanned it on Oct. 10 in Baltimore, cops attempted to pull him over, sources said.

Howard — armed with 9mm handgun — briefly gave chase before being apprehended, sources said.

Howard was infatuated with his married tenant and had been sneaking into her apartment, sources have said.

Howard has not been charged because he is still in Maryland pending extradition.