Dallas police got a surprise last week when they expected to save a woman from a sexual assault. 

After a six-hour standoff, they stormed an apartment with a SWAT team, only to find the house had been empty the whole time. 

Police were responding to a 911 call from a girl screaming that she had been sexually assaulted by a group of men. 

Apparently the girl had fled the apartment and called from a local bus stop. 

Neighbour Debby Hall said she saw the victim shortly after the alleged attack and helped her find a phone to call 911. 

"She was severely beaten up, her eye was black and her nose was broke.  I was trying to tell her there was a hospital over there but she was too nervous and scared."

Police suspected the girl was inside with the armed suspects, but it turned out no one was inside.

SWAT officers used a loudspeaker to address the empty apartment for six hours before storming the complex.

Over 22 officers surrounded the apartment in the standoff.

This isn't the last time this week that Texas police have been left with a bit of a red face.   On Wednesday night in Nashville, an officer saw an 'altercation' in a car a fired four shots into the car. It turned out to be a couple of newlyweds having some fun.