The proper use of cameras, perimeter and firepower.

A Texas homeowner fatally shot two masked men late Friday after they posed as officers serving a warrant and opened fire on the house, police say.

The Houston Police Department responded to reports of gunfire in the southeast part of the city around midnight, Officer C. Jones told Fox News Digital.

The suspects were wearing bulletproof vests marked with "police," but no patrol cars or flashing lights were present, raising the homeowner’s suspicions, authorities said. The two men were also wearing masks covering their faces and badges around their necks, Fox 26 Houston reported, citing the police.

"They became suspicious because they have a Ring camera and the suspects were stating they had a warrant, but it's just two people, and they're masked up and no police cars, no lights or anything like that," Lt. Khan told Fox 26.

Texas homeowner kills fake police who opened fire on their home in Houston area | Fox News

The homeowner felt something was not right and followed his gut. I have no idea if he did or did not, but I would have called 911 to report and check if there was a warrant to be served at my location. He also did not open the door to check if they were real cops truly serving a warrant, perimeter remained intact.

But then, there was the final indictor that these were naughty boys:

Police said the men fired into the home before the residents returned gunshots, killing both, the local station reported. Arriving officers attempted CPR, but the men were pronounced dead at the scene, the outlet added.

That removed all doubt the homeowner may have had.

Cameras were used, perimeter was not broken, fire was returned: successful self-defense.

Holes can be patched, blood can be cleaned. Life comes first.