  Centimeter continuum observations of protostellar jets have revealed the
presence of knots of shocked gas where the flux density decreases with
frequency. This spectrum is characteristic of nonthermal synchrotron radiation
and implies the presence of both magnetic fields and relativistic electrons in
protostellar jets. Here, we report on one of the few detections of nonthermal
jet driven by a young massive star in the star-forming region G035.02$+$0.35.
We made use of the NSF's Karl G. Jansky Very Large Array (VLA) to observe this
region at C, Ku, and K bands with the A- and B-array configurations, and
obtained sensitive radio continuum maps down to a rms of 10 $\mu$Jy
beam$^{-1}$. These observations allow for a detailed spectral index analysis of
the radio continuum emission in the region, which we interpret as a
protostellar jet with a number of knots aligned with extended 4.5 $\mu$m
emission. Two knots clearly emit nonthermal radiation and are found at similar
distances, of approximately 10,000 au, each side of the central young star,
from which they expand at velocities of hundreds km s$^{-1}$. We estimate both
the mechanical force and the magnetic field associated with the radio jet, and
infer a lower limit of $0.4\times10^{-4} $M$_{\odot}$ yr$^{-1}$ km s$^{-1}$ and
values in the range $0.7-1.3 $mG, respectively.
