The onset of the >10 MeV proton event of August 13-14, 1996 
revealed a velocity dispersion which is a signature of its solar origin, 
but no associated soft X-ray flare was observed. The LASCO CME 
observations, the presence of AR 7981 beyond the west limb, and Type II 
and IV radio burst timing with respect to the proton event onset indicate 
that the parent solar eruption may be centered on the back side of the 
Sun, at about 150°W. In such a case, expanding CME-associated wave can 
reach the Earth-connected interplanetary magnetic field line in about one 
hour and so give rise to the >10 MeV proton event observed with the 
Energetic and Relativistic Nuclei and Electron (ERNE) instrument onboard 
SOHO. We verify this hypothesis against observational data and conclude 
that a solar back side eruption is the most plausible explanation of the 
August 13, 1996 event. We compare the August 13, 1996 event with events 
associated with Earth-directed CMEs, and show that the August 13,  1996 
event reveals many properties common to >10 MeV proton events originating 
from solar eruptions centered ~90° away from the root of the 
Earth-connected interplanetary magnetic field line. In such events, the 
first detected protons are released about one hour after the start time 
of Type II and IV radio bursts. The first injection spectrum is 
essentially harder than the spectrum at the intensity maximum, i.e. the 
hard but less intensive proton production is followed by the major 
soft-spectrum production when CME expands farther from the Sun.