The TV journalists may be doing an investigative piece about, let's say, drug use among the student population in your area. They will obtain information from arrest records (which are public records) and probably from, as Ohiogal said, "witnesses", or students in the area, juvenile detention centers, whatever. They will not "release" any information, except when all of the information is gathered, verified, and ready for broadcast. Then you will see it on the news.
Law enforcement officials, likewise, will not compromise an investigation by releasing information prior to completion of their investigation (although "leaks" may occur, and will sometimes appear on the news as coming from "unnamed sources close to the investigation").
The only information readily available for those interested in learning more about an ongoing investigation is from public records, such as the arrest record. Unless you do your own investigation to discover what is going on, you must wait until both the sheriff and the journalists are ready to present what they have learned.
Journalists are allowed to "publish" the names and ages of anyone listed on an arrest record or anyone involved in a court action, by the way. Legally they are able to do this. Journalists often have to make the decision as to whether to include certain information or withhold it, however. It is a common practice, for instance, for journalists to withhold the names of sexual-assault victims, although legally nothing prevents them from doing so. It is an ethical decision. Likewise, many journalists, but certainly not all, will refrain from naming juvenile suspects until formal charges are brought.
