In postincident interviews, both incident pilots stated that, during their first approach, they believed the lighted runway on their left was 28L and that they were lined up for 28R. They also stated that they did not recall seeing aircraft on taxiway C but that something did not look right to them.
Much more detail here in the NTSB link:
https://www.ntsb.gov/investigations/...CA17IA148.aspx