The 78-year-old Reno man has been charged with the murders of four women -- two Bay Area women who were killed in the late 1970s and two Yuba County women whose bodies were found in 1993 and 1994.
Healdsburg police said Tuesday that their city was referenced in some of Naso's writings, prompting investigators to review local unsolved cold cases.
At a preliminary hearing in Marin County Superior Court, investigators testified that they had found a document in Naso's home that lists nine "girls" and one "lady" with geographic locations written next to each.
Number one on Naso's list is a reference to a "girl" in Healdsburg.
Healdsburg police said an unsolved homicide from the early 1980s involving an unidentified female victim was reopened to determine if there is any link to Naso.
The victim's body was exhumed in April, and a secondary autopsy was performed, police said.
Further evidence from the case is being re-examined and tested using new technologies that were unavailable during the initial investigation.
Healdsburg police are awaiting test results in the case.
The evidence so far has not implicated Naso, and he is not considered a suspect, police said.