I was looking for a fugitive and his brother crossed the lines of propriety and got thumped up. I left my business card and the fugitive's incarcerated dad called my office from a recorded line at the pokey and left a recorded message at the FBI office promising to kill me when he got out. I went to the jail and interviewed him, where he admitted to making the call and apologized.
I was going to let it go but by then supervisors were involved and he got the full ride scholarship to the Bureau of Prisons.
Was working a burglary/receiving stolen property case and had occasion to arrest the perpetrator, who was 'legal advisor' (high school diploma, no legal ed) to a violent militia group. Right after he bonded out I started getting obscene & threatening phone calls at home - my wife and kids heard them when I was working.
In those innocent days, the DA issued a phone trap (not tap) order to AT&T; they set up my phone so a fast double-click would set the connection until AT&T reset it. Sure enough, the next call came in and the trap worked perfectly. However, the perp was not a militia-type; it was some kid I'd cited for speeding a couple of times.
Neither his dad nor the juvenile judge were all that amused by the recorded content of his calls.
Just goes to show that what you suspect is not always what is.