  In this article we study the prospects of the proposed Large Hadron electron
Collider (LHeC) in the search for heavy neutral scalar particles. We consider a
minimal model with one additional complex scalar singlet that interacts with
the Standard Model (SM) via mixing with the Higgs doublet, giving rise to a
SM-like Higgs boson $h_1$ and a heavy scalar particle $h_2$. Both scalar
particles are produced via vector boson fusion and can be tested via their
decays into pairs of SM particles, analogously to the SM Higgs boson. Using
multivariate techniques we show that the LHeC is sensitive to $h_2$ with masses
between 200 and 800 GeV down to scalar mixing of $\sin^2 \alpha \sim 10^{-3}$.
