The Hounslow school teacher who jumped in front of a tube at Osterley station was at the centre of a child protection probe.
Lampton School tutor Savraj Powar, 43, was hit by a London-bound Piccadilly Line tube in front of dozens of shocked rush-hour commuters at 9.15am on Tuesday.
It is understood Hounslow police's Child Protection Team planned to arrest the suspended science teacher on suspicion of an 'inappropriate relationship' with a 17-year-old pupil at the Lampton Road school.
But Mr Powar made off in his car and drove immediately to Osterley station, where witnesses said he flung himself in front of the oncoming train.
Investigators later removed a vehicle from the station car park for analysis.
Last month, the Chronicle reported how the 43-year-old was found lying in a pool of blood in the car park of the nearby Hare and Hounds pub. Police now believe this was an unsuccessful suicide attempt.