The Red Bull team boss was quizzed on Friday by a lawyer for several hours on charges that relate to his behaviour towards a female employee.

A spokesperson for Red Bull said: "It would not be appropriate to comment before the investigation is completed."

Horner has denied the claims to Dutch newspaper De Telegraaf, external.

It is unclear whether the matter will be resolved before Red Bull's 2024 launch at their Milton Keynes factory on 15 February, where their new car is set to be unveiled.

Red Bull are still planning for the event to go ahead.

The investigation into Horner could take weeks, and there are even questions as to whether it will be completed in time for the start of the season.

Pre-season testing takes place in Bahrain from 21-23 February. The first race of the season, also in the Gulf state, is on 1-3 March.

The company said in a statement earlier this week that it was taking the situation "extremely seriously".

The Horner question will inevitably overshadow Red Bull's launch. Even if Horner is there, he is unlikely to be able to able to answer questions about it, but it will be a focus of attention in enquiries towards him and drivers Max Verstappen and Sergio Perez.

The controversy is taking place against a backdrop of reports of splits and tension within Red Bull, among them claims that motorsport adviser Helmut Marko and Jos Verstappen, the father of Red Bull's three-time world champion Max, have taken against Horner.

Red Bull, Marko and Verstappen have so far been silent on all such matters.

Despite the disruption, Verstappen and Red Bull will start the season as hot favourites to win a fourth consecutive world championship.

The Dutchman, 26, dominated last season, winning 19 of the 22 races among a string other records. Mexican Perez won two of the remaining three races as Red Bull finished first and second in the drivers' championship for the first time in their history.

Their acclaimed chief technical officer Adrian Newey has said the new car, the RB20, will be an evolution of its ultra-successful predecessor.

Most in F1 expect it to remain the fastest car on the grid; the main question heading into the season is whether any of the team's main rivals - Mercedes, Ferrari, McLaren and Aston Martin - can close in enough to make the season competitive.