Social media can be a useful tool for law enforcement in tracking criminals and solving cases, but criminals are finding it handy as well, Harold Thomas, criminal investigator with the Brownwood Police Department, told members of the Brownwood Rotary Club on Wednesday.

“Are you on social media?” Thomas asked his audience. “I have it, and I hope it scares you as much as it does me.”

Thomas, whose 36-year career includes working as a hostage negotiations trainer for Odessa Police and as chief of police in Hutto, discussed information he brought home after attending social media workshops last month at the Homicide Investigators of Texas annual conference. He has been on the Brownwood Police force almost four years.

“If you think your information is safe, it’s not,” Thomas said. “How many have privacy settings on your Facebook account? It doesn’t matter. Hackers can get around it.”

Personal information shared on social media, along with other details stored on phones and imbedded with photos and posts, provides criminals with a surprisingly complete overview of an individual’s private data, habits and location.

Thomas reminded the audience of several basic privacy practices, including using complex combinations of characters for passwords, and then changing them every three to six months — even though that will make them difficult for legitimate users to remember.

“You would be surprised how often ‘1-2-3-4’ or ‘4-3-2-1’ works,” Thomas said. “People want something easy like that so they can remember it.”

He likewise urged avoiding passwords with easily accessible digits and words like phone numbers or family names. Care should be used in opening and replying to emails from unknown senders and addresses, because huge email centers exist solely to generate scams.

“They are making billions of dollars,” Thomas said.

He also recommended not uploading photographs while traveling, because it notifies the world where you are.

“If your Facebook page shows you’re in Dallas, a criminal knows you’re not home right now,” Thomas said. “Crooks love to know this.”

While offenders have become quite savvy in the use of social media to assist them in targeting victims, law enforcement has countered with expertise of their own. Without going into details, Thomas described websites and online tools that provide legal ways to investigate crimes, and even allow police to track activity within a specific geographic location.

“Maybe students send messages about a fight that’s going to happen, and they give a time and place,” Thomas said. “Then they’re surprised when we’re there waiting for them.

Crimes don’t have to be committed online for technology to help police.

“Criminals usually like to brag afterward,” Thomas added. “Investigators can monitor Tweets in a certain area and see who’s talking about it. Sometimes they even confess they did it.”

He said he visited an office of the FBI where a few traditional agents were seen working, but a much larger number of online experts were in the back monitoring electronic messages going overseas.

“They can’t read everything,” Thomas said, but they do receive alerts when certain keywords are used.

Technology has become so important, he added, that agencies like the Brownwood Police Department could benefit from having a “computer genius” on staff. Typical investigations can result in investigators downloading thousands of pages of data from a seized cell phone that need to be analyzed.

Apps that prove useful to cell phone users, like those that identify the location of another phone, can also help find suspects. While information on suspects’ cell phones can be helpful, Thomas said, certain information cannot be accessed without a warrant or subpoena. Modern technology can lead to situations where freedoms of speech and privacy intersect.

“Everything leaves a data trail on social media,” Thomas said. “Actually, it’s scary. With just a little bit of information from different locations, someone can stalk and find you.”

For example, he said police officers try to protect their home addresses for safety purposes, but that information invariably shows up somewhere — and it can be difficult to remove.

Online tools can generate information such as how many times and where, for example, a photo you posted online has been shared or used for another purpose without your permission or knowledge.

“Some of it approaches facial recognition,” Thomas said. “You can have a photo of (someone) wearing a patterned shirt, and get a list of posts of people with a patterned shirt everywhere online.”

Meanwhile, free sites available to the public — and criminals — facilitate things like making phone calls and sending emails anonymously.

Technology exists, too, that allows someone within Bluetooth range to secretly extract data from a nearby phone, if a device’s Bluetooth services are enabled.