Jos Verstappen on Thursday said he doubts the latest accusations about Fernando Alonso are true.
Now driving for Ferrari, Alonso responded in Spain earlier this week that he tends to "ignore what is said from other countries".
"You have to wonder if the accusations are true," wrote former Grand Prix driver Verstappen in his latest column for Dutch newspaper De Telegraaf.
"I cannot imagine that a driver would go that far. I don't want to say too much about it except that I have my doubts," he added.
The Dutchman also described as "ridiculous" Bernie Ecclestone's proposal to spice up grands prix with artificial rain.
Speaking to BBC radio on Thursday, Mark Webber agreed.
"Think of guys like Ayrton Senna and Jackie Stewart and Jimmy Clark and they would be ... well, Jackie is still here but the other two would be turning in their graves at the thought," he said.