  We propose a new explanation of the intriguing LSND evidence for electron
antineutrino appearance in terms of heavy (mostly sterile) neutrino decay via a
coupling with a light scalar and light (mostly active) neutrinos. We perform a
fit to the LSND data, as well as all relevant null-result experiments, taking
into account the distortion of the spectrum due to decay. By requiring a
coupling g ~ 10^{-5}, a heavy neutrino mass m_4 ~ 100 keV and a mixing with
muon neutrinos |U_{mu 4}|^2 ~ 10^{-2}, we show that this model explains all
existing data evading constraints that disfavor standard (3+1) neutrino models.
