  The sustained gamma-ray emission (SGRE) events from the Sun are associated
with an ultrafast (2000 km/s or greater) halo coronal mass ejection (CME) and a
type II radio burst in the decameter-hectometric (DH) wavelengths. The SGRE
duration is linearly related to the type II burst duration indicating that >300
MeV protons required for SGREs are accelerated by the same shock that
accelerates tens of keV electrons that produce type II bursts. When
magnetically well connected, the associated solar energetic particle (SEP)
event has a hard spectrum, indicating copious acceleration of high-energy
protons. In one of the SGRE events observed on 2014 January 7 by Fermi/LAT, the
SEP event detected by GOES has a very soft spectrum with not many particles
beyond 100 MeV. This contradicts the presence of the SGRE, implying the
presence of significant number of >300 MeV protons. Furthermore, the durations
of the type II burst and the SGRE agree with the known linear relationship
between them (Gopalswamy et al. 2018, ApJ 868, L19). We show that the soft
spectrum is due to poor magnetic connectivity of the shock nose to an Earth
observer. Even though the location of the eruption (S15W11) is close to the
disk center, the CME propagated non-radially making the CME flank crossing the
ecliptic rather than the nose. High-energy particles are accelerated near the
nose, so they do not reach GOES but they do precipitate to the vicinity of the
eruption region to produce SGRE. This study provides further evidence that SGRE
is caused by protons accelerated in shocks and propagating sunward to interact
with the atmospheric ions.
