"A stranger had come in through an open door and attacked this woman."
Mike Hanson with Madison police says that attack happened Tuesday morning on Madison's east side.
A man sexually assaulted a woman so violently, she was injured.
He entered her home through an unlocked door.
"It's so important in this day and age whether you're here in this town or anywhere else that crime can happen anywhere, that you lock your door," emphasized Hanson.
Security experts say most criminals are opportunistic, and look for the easiest target.
Something as simple as a deadbolt may deter them.
A professional can install one for about 85 dollars.
"Be sure your home is lit. Light up exterior doors, doesn't have to be flood lights, just anythign that would show the presence of someone approaching the house," says Steve Beckmann with J & K Security Solutions.
If lights and locks offer too much leeway, arm your home with an alarm system.
"You can have a security system put in and just have it locally alarmed which would just be sounding within the house. The next step would be having the actual system monitored so that a monitoring service would take over at the point of entry, make a call to the house, shortly followed by a call to the police."
But even if your castle doesn't resemble Fort Knox, simply turning a lock, is likely to turn away a criminal.
Most security systems cost anywhere from $800 to $2,000.
Figure an additional $20 a month fee for a monitoring system.