No doubt premeditated. LE has suggested that the person who did this knew her. If they searched GE's house twice then they had probable cause to do so. Do they have enough evidence to convict? I'm sure this might have something to do with why they are being so quiet. They don't want to tip off anyone who might try to get rid of evidence. LE is watching a few people, no doubt.
I don't like to wildly speculate. Is it possible GE had help from people in San Diego? Perhaps. It is also possible she hired someone. Yet, everything up to this point seems to fit the bill of ONE perp, not several. It didn't appear to be a team effort. The more people you add to a situation like this on the perp side, the more things that can go wrong, people that can talk and offer testimony, and it becomes a huge mess. I'd bet this was done by a single individual male or female with decent knowledge of the area.
The pings on her cell phone hint to four LOCAL cities. If you know the area, it isn't hard to get to I5 from Hayward using 580 but if the cellular pings are accurate: Oakland, Hayward, Union City, and Fremont - then it's clear the person was looking for a place to put Michelle. TV makes hiding a body SO easy. It isn't. They certainly wouldn't be driving Michelle all the way down to San Diego. It's too much risk. I'd also point out that WHITE scrubs are very easy to spot from the air or at a distance.
There is a limited time frame from the time Michelle left the building to the time she was reported missing. The walk from the building or parking garage to where her car was located is less than fifteen (15) minutes.
No, my suspicion all along is the same LE appears to have - Michelle Le is in this area some place. She will be found, God willing.