Just found this...
https://www.youtube.com/watch?v=tkAeecnIlz4
whactya
At the beginning, it looked like Bobby Rahal (inside row 5) nudged Raul Boesel (outside row 4) from behind just before the turn which pushed him into Teo Fabi (inside row 4) who then hit the wall. But, even before this nudge, Raul was on a trajectory that would force Teo into the wall anyhow. The nudge just made the contact more uncontrolled. First turn of the race and Raul and Bobby were leaving no margin for error. So their race ended in less than 10 seconds.