He told the court the hairs were comparable and he could not rule out the fact they all came from the victim; before they were sent for DNA testing.
The witness has spent the day painstakingly detailing blood stains at the scene on Strathallan St where Ross' body was found at 2am on December 2 last year.
She was found face down in a pool of her own blood not far from a white van, which she drove as a supervisor at Spotless Cleaning Services. Inside and outside the van were a variety of different red marks.
Gillespie pointed out blood stains on the vehicle's exterior, some of which came from contact with a bloody object and others which were "spatter". The pattern of the spatter, he said, showed at least two of the stains came from "separate events".
During his examination of the scene Gillespie also found blood under the van, which he said was consistent with it being moved after the incident.
Near Ross' body was a wooden-shafted broom with a blue plastic head, which the court previously heard she regularly used to prop bins open while she loaded rubbish into them.
The item was produced as an exhibit and shown to the jury for the first time this morning before Gillespie pointed out further blood stains he had found upon it.
Some marks, he said, were "consistent with the broom impacting a source of blood".
Two more scientific witnesses are expected to give evidence this afternoon before a telecommunications employee testifies about cellphone towers in reference to Merritt's phone.
The trial is expected to run until the end of this week.