Detailed forensic analysis of the balcony that collapsed is continuing this weekend, as well as tests on another balcony on the same building judged "unsafe" by City of Berkeley construction experts.
Officials have confirmed that a criminal investigation will be recommended if negligent or sub-standard workmanship is discovered in the Berkeley complex and the balcony from which six students fell to their deaths and seven more were injured - two critically.
The fourth-storey timber-supported balcony of the Library Gardens complex catastrophically failed at 12.41am last Monday in San Francisco as the youngsters gathered for the 21st birthday party for one of the Irish students.
A City of Berkeley safety inspection later ordered a second balcony to be removed after ruling it was "structurally unsafe".
All balconies on the complex will remain closed. Forensic engineering analysis is taking place in a secure location.
Berkeley Mayor Tom Bates said he will ask the Alameda County attorney general to commence a criminal investigation if any evidence of negligence is found.
The City of Berkeley said it is still too early to confirm a definitive cause for the tragedy. However, dry rot is now widely suspected to have led the balcony to fail on a five-storey building which was only completed in 2007.
"In my view, there is a high probability it will be dry rot," Mayor Bates said.
San Francisco is now conducting a city-wide safety inspection of all similar balconies.
The Library Gardens complex is a 'podium style' structure, commonplace in California, in which the bottom storey is of concrete construction with the four upper floors all timber-framed.
The safety review came after the Library Gardens builder, Segue Ltd, was found to have settled two civil cases taken against it in the Bay area for water-damaged balconies.
Segue rejected any suggestion that two lawsuits against it of $3m and $3.5m over improper water-proofing of balconies in San Jose and Millbrae were, in any way, linked to the Berkeley incident.
Segue insisted the incidents were totally unrelated to the Berkeley incident.