It was mentioned in the article that I linked further up the thread, but the most famous case of a parent protecting a child who was a prime suspect (with a lot of physical evidence linking him to a premeditated murder), was the Sheinbein case in the mid-1990's. In that case, the high school student (age 17) actually advertised, by word of mouth, that he was looking for someone to kill, and would reward the person who brought him a victim. The killing was horrific, and they tried to frame a 3rd classmate for it and got caught when that failed. The boy's father, a patent attorney who was a childhood emigrant from Israel, heard that the police were seeking to arrest his son for the murder, so he met the boy in hiding, brought him a passport and money, and drove him to JFK to catch a flight. At the time, Israel did not extradite Israeli citizens to other countries. The whole thing wound up becoming an international incident, and is now shorthand for nightmare extradition situations. In a compromise, the son was tried for the crime in Israel, convicted and imprisoned there; he later died in an escape attempt in which he shot several guards. The father, who was disbarred for his actions, now lives in Israel; he cannot return to the US because there are still outstanding obstruction of justice charges here. The kid's siblings ended up changing their names; one now lives in Israel, the other is in the US. (I summarized & glossed over a lot; google Samuel Sheinbein if you want to read the entire story.)
One of the interesting things I notice about these cases is that when they begin with a big press bonanza over a missing person they tend to be forever known to the public by the name of a female victim, while cases that don't have that factor, even if there were multiple victims, almost always become known by the name of the convicted (or assumed) perpetrator. There are exceptions, of course, but that's the pattern. Why does the public so often canonize these particular victims but not the ones that are found right away?