First post here: I know a lot about VN culture, having lived in VN community for a long time. Here are a few points to consider:
1. Very common in Vietnamese weddings for old boyfriends or girlfriends to be invited to wedding, or to just come on their own accord when they hear about it, often traveling very far (1/2 way around the world). Often they will try to disrupt to wedding or make a last plea. These VN men are overly romantic and think that it is their fate to marry the bride. I even saw some cases where they showed up w/head shaved to prove their love. Usually they would go to brides house, and be very open about this, sometimes the parents may encourage it or fail to realize the potential risk, for example, they might think the old boyfriend was a nice guy, he just sad because your getting married, so the daughter should be nice to them in their last days before marriage. In the worst case, they will come to the wedding ceremony/reception and cause a scene to make their former bf or gf lose face in the community. For this reason, VN people have a proverb that when you decide to marry someone you should do it quickly (lay vo lien tay), or else third parties may try to cause problems, so they often avoid long engagements.
2. Re marrying outside of the culture: Can be acceptable, encouraged or discouraged, really varies from family to family based on their education level. If her family had a low level education, they may oppose marrying outside. To be honest, they will think that by marrying outside the culture, the groom may support the family in the long run less than a VN man or may not be quite as loyal, but, here someone earlier posted that the groom is half-chinese, so is part asian, hard to guess on this point. On the other hand, marrying outside the culture for women is good because often VN men do not allow the wife's parents to live with the family in the future (they only allow their own side to live with the family, because it is considered somewhat of a disgrace to live with the bride's family). It all depends on her family and not enough information on this point to judge.
3. Another possibility is he has an old gf that wanted to break up the wedding.
4. Many VN woman do get pregnant before marriage, as after engagement it is often considered not too taboo for the couple to have relations, and this is not a big deal provided that it is the groom's child of course. So, they do have a lot of quickly arranged marriages after engagement.
5. It does not sound like she got cold feet, but sounds like something happened to her. My guess is that the perpetrator is probably someone in her circle at the lab. It seems unlikely that an ex-bf would dare to enter the building, but maybe someone called her and she went outside to meet someone quickly, and then was attacked/abducted.
6. I read she is from Placerville, I believe that is near northern CA and they have a lot of HMONG people up there. Many who immigrated from Laos or Vietnam, they have a tradition of kidnapping brides before marriage, but their tradition is to break into the brides homes at night, there have been many cases of this in Northern CA. This is a remote possibility, but wanted to mention it.
7. Seems to me very unlikely a thief would go in there in broad daylight.
8. She may have a full VN name, but can't find it yet on Internet.
I pray that they can find her alive. She seems to be so bright and focused.
