  Previous researches on high-energy neutrino events from gamma-ray bursters
(GRBs) suggest a neutrino speed variation $v(E)=c(1\pm
E/E^{\nu}_{\mathrm{LV}})$ with ${E}^{\nu}_{\rm LV}=(6.4\pm 1.5)\times10^{17}~{
\rm GeV}$, together with an intrinsic time difference ${\Delta {t}_{\rm
in}=(-2.8\pm 0.7)\times10^2~{\rm s}}$, which means that high-energy neutrinos
come out about 300~s earlier than low-energy photons in the source reference
system. Considering the possibility that pre-bursts of neutrinos may be
accompanied by high-energy photons, in this work we search for high-energy
photon events with earlier emission time from 100 to 1000~s before low-energy
photons at source by analyzing Fermi Gamma-ray Space Telescope (FGST) data. We
perform the searching of photon events with energies larger than 100~MeV, and
find 14 events from 48 GRBs with known redshifts. Combining these events with a
$1.07~\rm{TeV}$ photon event observed by the Major Atmospheric Gamma Imaging
Cherenkov telescopes (MAGIC), we suggest a pre-burst stage with a long duration
period of several minutes of high energy neutrino emissions accompanied by high
energy photons at the GRB source.
