I would think so. In the case I mentioned the police bugged the suspect’s car, home, home landline, and his friend weared a wire.
The difference may be that the missing girl’s car had been found with her bloodstains, so they knew she was murdered. But only local police were investigating. In Summer’s case the TBI is involved. I’d think they could bug DW’s pens and pencils if they wanted to.
Or put a slap and track gps under their vehicles.