Could David Westerfield have been in Danielle Van Dam’s bedroom without leaving any evidence?

Why did the Van Dams vacuum the night of February 3rd?
On March 12th 2002, Dorie Savage, forensic specialist, testified:

Dusek: In particular, I’d like to direct your attention to the date of February 2nd of this year and ask if you were called upon to perform any tasks in the investigation of the disappearance of Danielle Van Dam?
Dorie Savage: Yes, I was.
Dusek: In particular, on February 2nd of this — yes, of this year, 2002, were you asked to go to the location of the victim’s residence?
Dorie Savage: Yes, I was.

Dusek: Can you describe what was the flooring in the room?
Dorie Savage: The flooring was carpet, and I was actually down on my hands and knees examining this carpet.
Dusek: Did this carpet appear to be freshly vacuumed in any manner?
Dorie Savage: No, it did not.
Dusek: What leads you to that opinion?
Dorie Savage: Well, there were items all over the floor. There were little pieces of what looked like maybe a sequin or something like that, and I didn’t see any vacuum marks that you would expect to see if it were freshly vacuumed.

Comments: There were items all over the floor and little pieces of sequin. How did Westerfield manage to walk in Danielle’s bedroom without collecting any of this little pieces of sequin? How did he manage to walk over items all over the floor without making any noise and leaving no evidence?

Dusek: When you left ultimately, I think you said, what, just before dawn — I’m sorry. Was it around 5:30 in the morning?
Dorie Savage: I think, yes.
Dusek: Had anything been vacuumed from the time period when you arrived to when you left?
Dorie Savage: No.
Dusek: When you left on February 3rd; is that correct?
Dorie Savage: That’s correct.
Dusek: Did you have occasion to then return to the residence?
Dorie Savage: Yes, I did.
Dusek: When was that?
Dorie Savage: On February 4th.
Dusek: Do you recall roughly what time?
Dorie Savage: Around 10:00 in the morning.
Dusek: Was that to conduct a further search?
Dorie Savage: Yes, it was.
Dusek: What did you do, basically if you can kind of capsulize it, when you returned later — I’m sorry — on February 4th?
Dorie Savage: On February 4th we went back in and looked through the room again, and we further searched the house for any more evidence that we might find.
Dusek: Was there any indication of anyone having conducted any vacuuming when you returned, that is between the time you left and when you returned on the 4th?
Dorie Savage: In what area?
Dusek: Any part of the house.
Dorie Savage: In the stairwell.
Dusek: And that is the stairwell that one would have to walk up?
Dorie Savage: Yes.
Dusek: And had there been stairwell — I’m sorry — had there been powder used in that stairwell, as well?
Dorie Savage: Yes.
Feldman: I thought you said also that on your second time back into the residence it appeared as though the stairway had been vacuumed; is that correct?
Dorie Savage: That’s correct.
Feldman: Did you suggest to anybody that they should be doing any vacuuming while you were in the process of attempting to collect trace evidence?
Dorie Savage: I don’t believe I said I was in the process of collecting trace evidence.
Feldman: Oh, so on the second occasion that you visited the Van Dam residence, which I believe was the 4th, you weren’t there for the purpose of identifying or locating trace evidence?
Dorie Savage: On the stairs specifically? No.
Feldman: Anywhere.
Dorie Savage: In other parts of the residence, yes.
Feldman: So it’s correct that you went back a second time — your purpose in going back a second time was to collect trace evidence, right?
Dorie Savage: That would be correct.
Feldman: Now, my question, again, is did you direct anyone to vacuum this stairwell over which you had seen apparent blood stains?
Mr. Clarke: Objection. Relevance and argumentative.
The court: Well, overruled.
Feldman: Did you tell anybody to vacuum?

The witness: I did not.

Comments: Danielle was reported missing on Saturday February 2nd 2002, the Van Dam were not allowed back in their home by police, they spent the night of February 2nd to February 3rd at a neighbor’s house and came back into their house on February 3rd in the morning. The night of February 3rd 2002, (their first night in the house after Danielle’s disappearance), the Van Dams are busy vaccuming the place.
If they had nothing to hide, why did they vaccuum knowing the investigation just started?
Did they have nothing better to do? Was it to help the investigation?

Danielle Van Dam's last day - February 1st 2002
Could Westerfield identify Danielle's bedroom in the Van Dam's house?