The explorers did not interfere with them or speak to them.

Thus the representatives of the different races encountered.
The division under charge of Walker joined Fremont at the appointed rendezvous, but winter was upon them, the mountains were sure to be choked with snow and no one was familiar with the route.

As a matter of prudence, therefore, Walker was directed to continue southward with the principal party, while Fremont and a few picked men pushed on directly through the Sierras to Sutter's Fort, with a view of obtaining the necessary animals and supplies.
The smaller division was advancing as best it could, when a number of plainly marked trails were observed showing they were in the vicinity of some of the most notorious horse thieves in the world.

They were daring and skilful, went long distances, plundered ranches and hastened to the mountains with their booty.

The exasperated Californians often organized and went in pursuit, but it was rare they overtook the dusky thieves, and when they succeeded in doing so, were invariably defeated.
This sort of people were undesirable neighbors, and Fremont sent forward two Delawares and two mountaineers to make an investigation.