During the cross-examination of an earlier witness, Mr Yovich asked if anyone ever entered the DNA lab to work on the phones. 

Mr Edwards worked as a Telstra technician and serviced the Telco's business and corporate clients in the 1990s. 

Mr Yovich is now asking Mr Bagdonavicius to draw the lay-out of the Pathwest lab when it was situated in the QEII Medical Centre, J Block, first floor. 

He was also responsible for compiling a forensic review for WA Police in 2003 that included details of all the testing to that date that had been carried out on Ciara's 11 fingernail samples. 

Mr Edwards' DNA was allegedly discovered underneath a combined sample of Ciara's left thumb and middle finger (AJM40 and AJM42) in 2008. 

Mr Bagdonavicius said DNA testing developed in the late 1980s and1990s, but that he was "not the scientist in the DNA area". 

He has agreed that the introduction of the Profiler Plus testing to Pathwest lab in the "very late 90s" was a significant leap forward for the technology. 

He said he has some recollection of working on the Macro Taskforce cases, but cannot remember individual activities he carried out without referring to his notes. 

"This is certainly the longest case that I have been involved in," he said. 

Mr Yovich is now going through the witness statements Mr Bagdonavicius made, being one in 1995 relating to the Karrakatta cemetery rape victim case, and then several from mid-2016 onwards. 

Mr Bagdonavicius has agreed he relies on his documentation being accurate to assist with his recollection, given the passage of time. 

Mr Yovich is now asking about when the process for storing exhibits in the lab changed. The court has heard previous evidence Pathwest's storage coding system was introduced in late 1996. 

Today, an exhibit is given a barcode once it is retrieved which allows it to be scanned and tracked as it is processed in the lab. 

In the 90s, Mr Bagdonavicius said the process was manual. 

Ms Downe: Yes

AJM41 and AJM46 samples underwent a number of DNA extraction and amplification processes performed by Ms Downe in 2003. 

In 2004, when the exhibits were transported to a NZ lab for Y chromosome testing, a blank relating to runs the exhibits were on was found to have been contaminated with female DNA that was not Ciara's. 

It's not yet clear when and in what lab the contamination occurred, and testing to determine whose DNA it was was not undertaken at the time, as the NZ lab was only interested in trying to find male DNA. 

Mr Yovich is now going through the different blanks associated with the Pathwest testing runs for AJM41 and AJM46, and where each blank was stored in the freezer afterwards. 

Mr Yovich: If DNA is detected on a blank, what is the consequence? 

Ms Downe: If what might be part of or a DNA profile [is detected], then we look at where that DNA may have come from, because it should have no DNA in it at all.

Mr Yovich: If it has DNA in it, that may mean that the parent sample, the AJM nail exhibits, any DNA finding in relation to those may be invalidated? 

Ms Downe: We would look at that result and try to determine where that DNA came from and looking back at who handled the exhibit. 

Ms Downe said if a blank was found to be contaminated during a run, it should have been noted on documentation, and investigated. 

She said she does not recall a blank in the DNA testing process returning a positive for DNA. 

The state does not rely on the testing or results from AJM41 and AJM46 (Ciara's left and right index fingernails), which returned only Ciara's DNA. 

Mr Yovich has completed his cross-examination. 

During re-examination, Ms Downe has explained that the contamination of a blank does not always mean the entire run is invalid as it could mean the staff member handling the blank could have contaminated only the blank. 

She also explained Pathwest had a staff DNA database to cross-check if contamination was detected. 

She also transferred AJM49 and AJM50 into swab containers in preparation for testing. 

Mr Yovich is now asking her about how common it was to receive fingernail clippings as an exhibit. 

Mr Yovich: Are you able to tell us from your experience between 2002 and 2005 whether it was more common to receive a swab or scraping [rather than clippings]? 

Ms Downe: It's far more common to receive a swab of a fingernail.

She said there were no laboratory protocols for dealing specifically with fingernails at the time, and that she would have relied on her experience and advice from her manager, Mr Bagdonavicius, to determine the best way to examine the items. 

At the time she took the fingernails out of their containers, took photographs of them and then 'wet dry' swabbed the clippings to retrieve any cellular material. 

AJM49 had already been examined by another scientist, and Ms Downe put the fingernail clipping from AJM49 directly into the tube to undergo DNA extraction, rather than swabbing it. 

"We accept ... that the scientific literature suggests the chance of contamination is remote but secondary transfer is known and documented in the literature," he said in his opening address.

"Your Honour will have to consider the possibility of cross-contamination with other exhibits at Pathwest that did have the accuseds' DNA on them."

Secondary DNA transfer is where DNA is transferred to an object or person through an intermediate, such as a piece of laboratory equipment like forceps, or scissors.

Mr Edwards has pleaded not guilty to the murders of Sarah Spiers, Jane Rimmer and Ciara Glennon.