I agree it is far fetched.
But it can help explain some elements that don't make sense otherwise :
- listed as white for the US, but listed as coloured in SA
- in 1983, a SA political activist was assassinated in Paris because she knew too much. The shotgun in the mouth is in line with this type of motive
- 1983 was a hot year for the fight against apartheid :
http://www.sahistory.org.za/article/apartheid-1980s-grade-12
- sexual assault & rape were mean of torture in those days. So, if the shot is indeed politically motivated, the guy could have assaulted her
- the kind of clothing found & the IUD
- no ID because most SA fleeing the country left their dompass at the hands of relatives
- many disappeared not found per the TRC (Truth and Reconciliation Committee)
- Black & coloured missing reports were not accepted by the police in SA, so, no wonder the US police didn't know then
- SA anti apartheid political parties had ties with East Germany, which can explain the handwriting. East Germany was quite active against apartheid in those days
- her family might not know she had fled to North America, so was unable to claim her
I understand it is far fetched, but since our explored leads brought no results, we have to find other angles.
Checking with Telkom (the SA phone company) to find out what was phone numbers structure in those days.
I don't say that it's a 100% absolute correct theory, but it's a strong possibility to be explored. If it's not the right lead, be it, it's the wrong one and door is closed.
But at least, we get an answer with facts instead of only speculating.
If the straightforward path doesn't work, let take the problem the other way round is my motto for problem solving.
See what I mean ?