On 2017 September 10, the neutron detectors on the Earth surface were able to detect the second Ground Level Enhancement (GLE) of the solar cycle 24. This GLE was associated with a beam-like near relativistic electron event seen by the Electron, Proton, and Alpha Monitor (EPAM) particle instrument in the Advanced Composition Explorer (ACE). All the electron energy channels on EPAM show a nearly simultaneous rise as a result of near relativistic electrons being scattered from the detector and being counted in the lower energy channels. Through the analysis of modelled instrumental behaviour and using particle propagation codes, we infer that the release back at the Sun for this electron event happens at the time of the peak of the soft X-ray flare. This means that the particles, at least those which arrived firstly, are very likely from flare origin. Shortly after the onset of the event at the spacecraft, we see evidence of the arrival of mirrored particles at a magnetic bottleneck upstream of the Earth orbit. We discuss the implications for the event properties on other sites in the heliosphere.