[Tainan]

The Asian gang home invasion scenario was mentioned by one of the commenters. It sound like this is what happened.
Very professional attack on the dentists home. It was noted that one of the invaders finished off a cigarette prior to the break-in and pinched it off with is fingers and put it in his jacket pocket (caught on the CCTV security cam).
So, it does look like this might well have been an organized Asian gang home invasion. My guess, and its only a guess, is that the dentist is also Asian.

[Bogey78O]

Ehhh... it can go either way on if it was an asian gang or another type. The asian gangs in that area seem to be into the drug trade though and not the burglary route. Hell, most of the Vietnamese are either extended family or they know each other from church as the two places of worship pull in probably 90% of the population (Buddhist Temple and Queen Mary)