PIKE CREEK, Del. (WPVI) --To get inside the Arundel Apartments in Pike Creek, Delaware, you need to punch in a code.
It wasn't always like that.
But after a resident there was ambushed by a masked man with a gun, sexually assaulted and kidnapped last month, neighbors like John Wilson welcome the change.
"A lot safer, a lot safer," said Wilson.
It's a crime that New Castle County Police say was committed by the same man who terrorized two more women at two other apartment complexes, and now it's being investigated if he struck a fourth time - only a little further north in Pennsylvania.
Residents at the Madison Glen Mills in Chester Heights got a letter, just a few days ago, alerting them of a similar attack.
Pennsylvania State Police say this past Tuesday a masked man with gun ambushed a woman walking into her home.
But somehow the victim was able to bravely fight the suspect off.
"It's definitely scary," said Madison Glen Mills resident Katie Maloney.
She tells us she lives with her boyfriend, but says he can't always be around.
"It makes you nervous about going out by yourself," said Maloney.
With so many similarities with these crimes, we asked Pennsylvania State Trooper Timothy Greene if this is connected to the attacks in New Castle County.
He says the Pennsylvania State Police and New Castle County Police are working together now.
"We have been in contact with Delaware. However, at this time, we cannot say that this is connected with Delaware," said Greene.
In the third attack in Delaware, at the Preserve at Deacons Walk Apartment, the victim also escaped.
But the first two victims, one at the Arundel Apartments and the other at Top of the Hill Apartments in North Wilmington, they were ambushed, sexually assaulted, kidnapped and forced to drive to ATMs taking out cash for the suspect.
"There's a lot of messed up people in this world is what it comes down to, so hopefully they can catch him and put him where he belongs," said Madison Glen Mills resident Kyle Meader.
Now more than ever people are being asked to pay attention to their surroundings.
And if you see anything call police.