There needs to be clarification of the suitcase evidence as regards fibers and hairs. Can anyone help out with this?

Is lou smit, “quite convinced an attempt was made to place her in the suitcase.” Or does he just suggest it as a possibility? Is it just an idea or a conviction?

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off topic – but, not really:
I’ve often considered writing a fictional piece based on this crime using case evidence and the crime scene, etc and offering the killers motive as well as describing what happened in the house, a fictional account and nothing more than that. In this imagined tale the killer does not use the basement window as an entrance or an exit. Sometime before the night of the crime (or earlier in the day) he deposits a duffle bag or some such thing under the grate at the basement window. Inside are the note pad, confiscated on an earlier occasion, and the note already written and the cord and the tape and whatever else he thought he was going to need. On the night of the crime he’s just some guy walking down the street empty-handed, maybe empty pockets, too. so, he enters the house the same way he leaves, through the butler door, and he goes directly to the basement. He uses the suitcase to reach through the window into the space beneath the grate and retrieves his bag of tricks, disturbing the dust on the sill or ledge, dragging debris into the house. On his way back upstairs he leaves some kind of light source behind him and the door open so that he won’t be obstructed or hindered in any way when he returns with the child.