I'm really behind on this case, so please feel free to shoot holes in the following.
From my read, dogs lost Sierra's scent at the end of her driveway (
link ). Then you have a string of assaults at two Morgan Hill Safeways. One where the assailant used a knife and the other where he used a taser. (
link ) Later reports indicate Antolin Garcia-Torres, who worked at both Safeways, was tied by DNA to the taser assault. (
link ) Now, consider Sierra's last known location, the locations of the teen's items, her school, and where Garcia-Torres lived/worked (
link ), I'd bet dollars to donuts, the guy spent some time stalking her, to not only determine where she lived but to also get an idea of her and her family's routine, and then tased her the morning he abducted her.
Given the proximity of her belongings to her abduction, I think he continued on Hale Ave to Bailey Ave, and then took 101 back towards his work/home. Considering that his previous assault failed, I highly doubt he kept this girl alive. That is, he was/felt triumphant in catching his prey, but concerned he would be caught. So, imho, he likely murdered her shortly after abducting and raping her. Since they found her items so close to when she was abducted, this indicates to me, that he dropped those first. Hopefully, searchers have scoured Bailey Avenue. Esp around the treed area under the the area were Bailey Avenue crosses over coyote creek trail. (
link )
And finally, surely, the guy had a cell phone? If so, I would think LE executed a warrant with the carrier to obtain ping information. Which, if so, I think can ultimately be used to, at the very least, narrow down search locations.
Anyway, these are my thoughts, at this point. Please feel free to correct.