The other two things that helps law enforcement tremendously are being able to track where someone has been via their cell phones and the tracking of internet sites. Several times someone has been convicted based off their internet searches (i.e. how to get away with murder, how to dispose of a body, how to make a murder look like a suicide, etc.). People have been caught looking up sites such as these just days before a person has been murdered. People have claimed to be nowhere near a crime scene only to find out via their phones that they were.
Technology can be both good and bad. I'm so glad law enforcement has been able to use it to protect the citizens of our country.