We consider 10 tests which distinguish the source of energetic particles in upstream ion events. Some tests are definitive, and others inadequate. In particular, we note that the Fermi model requires a finite time of magnetic field line connection to the bow shock before energetic ions appear and inverse velocity dispersion when the interplanetary magnetic field rotates to a more radial direction but that these features are also expected of the leakage model under certain conditions. We present simultaneous magnetospheric, magnetosheath, and upstream energetic particle observations during two well-documented upstream events on November 1, 1984, and apply the 10 tests. The events are unusual in that they occured during a period when the magnetosphere was greatly compressed, provided for an increase in the energetic magnetospheric particle population and a decrease in the magnetosheath thickness. Magnetospheric leakage satisfactorily explains our observations on this day, but in situ Fermi acceleration does not. Consequently, we consider magnetospheric leakage a sufficient source for upstream particles during these two events. ¿ American Geophysical Union 1988