Don't forget about what we've heard from Beth too, that in a statement, Joran put them at his house at 1:40 am.
That still leaves approx 50 minutes for them to get to the racquet club area for the witness to see them at 2:30 ish. (Which also still leaves plenty of time for Deepak to have been seen washing the car at 3:30 is)

I agree with what so many have posted before me. The only reason why Deepak would be out washing his car at 3AM is if he had something to hide ie: destroying evidence. I can't think of a single alternative explanation.

First, there were no searches conducted by the Aruban police of the suspects’ cars or homes for 10 days following Holloway’s disappearance. Deepak was seen by neighbors cleaning his car at 4 a.m. on the night of her disappearance with a substance that was later determined to be bleach (he initially testified that he was removing sand from the car, and later changed his story to say that he was getting rid of ants).

Another witness says Kalpoe brothers were seen washing their car very thoroughly in what was said to be an unusual location near their home. This took place after their initial release from questioning and prior to their arrest. EquuSearch sought to check the area with dogs; however they were turned away by the Mother of Deepak Kalpoe.