A statement from the team said: “The circumstances which led to this tragic incident remain unclear for the moment. With respect to the whole family and all other relatives, Kiefer Racing will not take part in the Malaysian Grand Prix.”

Kiefer Racing runs Dominique Aegerter and Tarran Mackenzie in the Moto2 class.

The German, himself a former rider, founded the team with his brother in 1996, to run in the national and European championships. Kiefer Racing moved to the World Championships in 2003.

Its greatest success came in 2011, when his rider Stefan Bradl won the World Championship. This year the team celebrated victory at Misano with Aegerter, only to have it taken away with disqualification on a technical infringement.

Aegerter posted a tribute on social media, saying: “It’s a huge shock. My thoughts go out to his family and friends. He was definitely one of the best bosses I ever had, a fantastic person and a great friend.”

IRTA president Herve Poncharal spoke for the paddock, saying: “It is a sad and dark day. We have lost a true friend, and a very competitive team manager. He was full of passion and energy, and his death is a huge loss.”

By Michael Scott

Vazquez, Stefan Kiefer, Kent, Moto3 race, Grand Prix of the Americas, 2015