Police in Arlington, Texas have released footage of a tiny dog scaring off a home invader after they say he broke down the front door.

"Who says you need a big dog to protect your castle?" Arlington Police Department said in a post on Facebook. Police said the pup "saved the day" when a home invader kicked down the front door and headed to the bedroom, only to get spooked and run back out the front door when the tiny pooch started barking at him.

The hero mutt is a Chihuahua named Sadie.

Police are now asking anyone with information about the 18 May break-in to contact them. "We need to identify this guy." they wrote online, "He is described as an African-American male, 5-11, 225 pounds."

Though they might look small, chihuahuas can be fiesty characters to deal with. In April, Northern Irish police jokingly posted on Facebook that they had had to 'arrest' one Chihuahua they christened Nigel who they said was "an angry wee man" and "seriously anti police".