He tells the I-Team he tries to make it clear neighbors are watching.
"[To] deflect the situation so it doesn't continue to happen or so they stop," he said.
He feels it helps everyone keep their eyes open for criminal activity in the area.
In some cases, Captain Dan Baumann from the Waukesha Police Departments said snapping a picture like that is the best form of the Homeland Security motto "If you see something, say something."
"It's exactly what we want for our community members is to stand up," Baumann said.
He said sharing information helps police take action, but warns not to put yourself at risk.
"We don't want anybody to get hurt because they intervened," he said.
One example comes from the Bay View Town Hall Facebook page. In a post, a woman, who didn't want to talk to the I-Team, explains she started a conversation with a man she thought was breaking into a house. She took pictures of him and posted them.
Baumann couldn't comment on the post, but said in general, it's best to be careful about approaching people. He said if you accuse someone and it's not true, you could face a defamation lawsuit from that person.
"If we accuse somebody of a crime that hasn't been put through the court system, I think that's where the line gets drawn," he said.
It's something Diaz keeps in mind as he watches the neighborhood.
"You have to use your best judgment at that point," he advised.
And Bauman warns, if you want the criminals to see their day in court- you might consider keeping most of the information to yourself.
He worries some digital vigilantes could compromise the principle of innocent until proven guilty.
"Now we have information that would be held until trial and pieces of evidence that would be put in front of a jury, and now the public domain has seen that," he said.
If you do want to help police catch criminals, Baumann advises you collect any information you can safely. He also reminds people any recordings or information have to be taken legally for police to use them.
But Baumann said there is one exception to the principle of putting out as much information as you can. If you get your car, bike or other property stolen and you post the description, Baumann said it might help someone spot it so you can get it back- with the help of police.
Baumann explains you have to go through proper legal channels to stay safe.