An important radiation belt electron loss process is precipitation into the Earth’s atmosphere. The precipitation processes can be further categorized into individual fast precipitation events (bounce loss cone) and relatively slow and steady precipitation loss (drift loss cone). Analysis and quantification of both types of precipitation are essential to understanding the role that precipitation loss plays in the radiation belt. In this talk I will present a relativistic electron precipitation event observed at multi-points by the Colorado Student Space Weather Experiment (CSSWE), POES-19 and Balloon Array for Radiation belt Relativistic Electron Losses (BARREL). With the spatial and temporal information provided by the multi-points measurements, we are able to estimate the net loss of the 0.58-1.63 MeV electrons to be 6.8% of the total electron content between L=3.5 and 6 in this event. I will also show measurements of the quasi-trapped relativistic electrons, which are in the drift loss cone and will be lost within a drift period, by LEO satellites: CSSWE and DEMETER. We confirm that the inner belt quasi-trapped electrons are mostly produced by CRAND at very low L shells (L~1.2) by comparing their energy spectra with the theoretic calculation. We demonstrate that with this new source of inner belt electrons taken into consideration, the effect of the electron net loss due to slow pitch angle scattering of the stably trapped population into the drift loss cone is very different from the conventional understanding and needs to be re-evaluated.