Surveillance cameras and home security systems are becoming crucial tools for fighting crime, slowly replacing the neighborhood watch and its army of invisible street guardians.
Some of the biggest stories in recent weeks have involved surveillance cameras providing police officers with evidence to help solve investigations.
In the most recent case, a mystery woman was captured by home security cameras in Texas repeatedly ringing doorbells in the middle of the night with what appeared to be shackles hanging from her wrist, leading to a nationwide effort to track her down.
Montgomery County deputies said Wednesday that they've identified her, but will not name her because she is a domestic violence victim. Without surveillance footage, there's no telling what could have happened.
And in the case of Mollie Tibbetts, the jogger found dead in an Iowa cornfield this month, it was a neighbor's home security camera that offered a key clue on the suspected killer after mystified investigators searched for answers for nearly a month.
Then there's the case of Houston cardiologist Mark Hausknecht, who was killed by a man while riding his bike in broad daylight last month. In the days following the shooting, the motive and the suspect's identity remained a mystery until surveillance video obtained by a neighbor near the crime scene allowed investigators to identify the suspect.
Here's why home security systems are gaining popularity among investigators:
They're in real time and on your fingertips
Technology is advancing every day and home security systems are getting more sophisticated. Some provide immediate results, with the ability to take pictures of intruders, detect motion and alert homeowners if there's suspicious activity, including trespassing, vandalism and theft of packages.
Other systems allow homeowners to see what's happening around their homes through an app on their phones, and can be monitored from anywhere.
The growing interest in home security cameras means more options and better prices, experts say, with the cost varying based on several factors such as size.
Social media has made it easier to share the footage from home surveillance apps, especially on platforms such as Nextdoor that allow neighbors to post information specific to their particular areas.
The information is specific to the crime area
Authorities are using private video surveillance cameras to help crack down on crime, with some police departments urging residents to register devices with them.
In Illinois, the O'Fallon Police Department asked residents to help fight crime by investing in neighborhood surveillance cameras and registering them with authorities.
"Video surveillance is one of the best methods for apprehending criminals and convicting suspects who are caught in the act of committing a crime," the O'Fallon Police Department said in a statement. "Installing video surveillance is a great example of community-police partnerships and is something we highly value as a police agency serving our community."
Residents register their surveillance cameras with the police and provide information such as an address and a phone number so the O'Fallon Police Department can contact them when a crime occurs in their neighborhood. Once registered, investigators can reach out to them and request to see their video surveillance footage when a crime happens in an area.
"It's an extra set of eyes and ears in the community, because we can't be everywhere at every time," Capt. Kirk Brueggeman of the O'Fallon Police Department told CNN affiliate KTVI last year.
"It's not the holy grail of law enforcement, but it is another tool in our arsenal for finding people and solving crimes. The more cameras out there the better because it keeps people honest," he said.
While officers can access the data, it's not public record, according to the O'Fallon Police Department.
Invasion of privacy is a concern
Surveillance camera footage has its drawbacks. In some cases, people post footage of an alleged crime without verifying information, which can lead to misinformation. Such footage can cause mass hysteria, portray someone unfairly and also make the person who posted it a target for retaliation or lawsuits.