Team US F1's Formula 1 hopes appeared to be over on Tuesday, with high level sources revealing to AUTOSPORT that the outfit has now effectively closed down.
Against the backdrop of weeks of uncertainty about the future of the American team, which had been struggling to get a car ready for the start of the season, sources have revealed team personnel have now been informed they are no longer required as the operation could not continue in its present guise.
AUTOSPORT understands that shortly before lunchtime, production manager Dave Skog informed those staff who had remained at the team during its recent troubles that they were being put on unpaid leave - even though they remain technically employed.
That move, which has not yet been officially confirmed, effectively brings an end to the F1 dreams of team principal Ken Anderson and sporting director Peter Windsor who had hoped to create a genuine American grand prix team unless a fresh cash injection can be found.
It is understood that neither Anderson nor Windsor were present at the factory while the announcement was made, and neither was available for comment about the latest situation.
Calls to the factory switchboard have also gone unanswered, with a message stating that the number is temporarily not working.
The failure of Team US F1 to make it onto the grid means that there is now a vacancy for the Serbian outfit Stefan Grand Prix, which has been sitting on the sidelines for several months.
US F1 will need to be officially withdrawn from the championship if Stefan GP is going to have a chance of getting a late entry - although such a situation may be possible if FIA technical delegate Charlie Whiting's inspection visit to the American team's factory last week showed that the outfit was not capable of competing.
It is also not clear what US F1 investor Chad Hurley will now do. The American YouTube co-founder, who had invested in the team, has been linked with potential deals with both Stefan GP and Campos Meta in recent weeks - and it is possible he may choose to remain in F1 through involvement with another team.