SAN RAFAEL, Calif. » An investigator has testified that a diary detailing sexual assaults of women was found along with posed photographs of two Northern California slaying victims in the home of a suspected serial killer.

The lead investigator on the case made the disclosure Wednesday during a preliminary hearing for Joseph Naso, a Reno, Nev., man charged in the "Double Initial" killings.

Naso, 78, is acting as his own lawyer in what is likely to be a death penalty case. The former photographer has pleaded not guilty to four murder charges involving slayings of prostitutes the 1970s and 1990s. Testimony resumes on today.

"Girl in north Buffalo woods. She was real pretty. Had to knock her out first," read one entry in Naso’s journal.

Nevada Department of Public Safety Det. Richard Brown said the journal was filled with such descriptions, and that Naso used the word rape in other sections.

White-haired and wearing leg shackles, Naso sat alone at the courtroom defense table with his head rested on his hand.

Naso listened as Marin County prosecutor Dori Ahana and Brown detailed dozens of sexual and violent photographs of women seized from his home, objecting at times to the relevance. The photographs showed many women unconscious or appearing dead, including two prostitutes Naso is charged with killing, Pamela Parsons and Tracy Tafoya.

"Who is paying for all of this entertainment?" Naso asked after hours of detailed testimony about the photos. "This is my private work, my photography. The women have been violated. What happens in a home is sacred and private. … The whole thing is disgusting, and I don’t see the relevance at all."

Judge Andrew Sweet overruled Naso’s objection.

In one photograph of Parsons, Brown said she appeared to be dead.

"I thought she was deceased. Her face doesn’t appear natural," he said, describing the picture.

Other photographs taken of the lower halves of women appeared to show the reddish-purple discoloration of the skin seen in dead people, Brown said.

In a bedroom in Naso’s home, investigators also found a "List of 10" that contained scrawled descriptions of 10 women, including four references that prosecutors believe described murder victims — Roxene Roggasch, 18, Carmen Colon, 22, Parsons, 38, and Tafoya, 31.

The matching letters of each woman’s first and last names gave rise to the "Double Initial" moniker for the case. Six other women referred to on the list have not yet been identified, but prosecutors say the investigation is ongoing.

The preliminary hearing is providing the first in-depth look at the prosecution’s case against Naso and his lifestyle. At the end, the judge will determine if prosecutors have enough evidence to take Naso to trial.

Authorities seized thousands of documents, calendars, ledgers, journals and photographs from Naso’s house. In two safety deposit boxes, Naso kept $152,400 in cash, along with news clippings covering the slayings of Parsons and Tafoya, and other personal items from women.

Nevada probation Officer Wesley Jackson testified that he arrived in April 2010 to check Naso’s Nevada home for violations of his probation agreement and found food rotting on the kitchen counter and debris strewn about.

All the bedrooms were locked, and Jackson said Naso resisted opening them for a time.

In Naso’s bedroom, Jackson said, he found mannequin parts and a full mannequin clad in a red dress. Women’s lingerie was in the dresser drawers. In his garage, suitcases were found packed with mannequin legs clad in hosiery.

Further searches of the home turned up a box of knives and guns hidden behind a refrigerator in Naso’s garage, authorities said. Naso was forbidden to have weapons due to probation from a felony larceny conviction in California.

Parsons’ strangled body was found in the Yuba City area of Northern California in 1993, where Naso was living at the time with his mentally ill son. Court documents state that Naso had photographed Parsons.

A 1993 calendar Naso kept had an entry for Sept. 15, Brown said, that placed him in the area.

"Stayed in (Yuba City) all day long. Took care of some old business," Brown read from the calendar. "September 15 was the last time Parsons was known to be alive."

Tafoya was killed in the area when Naso lived in Yuba City. Her body was found on the side of Highway 70 near Marysville Cemetery in 1994.

In a calendar entry on Aug. 6, 1994, Naso referred to meeting with a woman in Marysville near the time of Tafoya’s death.

"Picked up a nice broad in (Marysville). 4 p.m. She came over for four hours. Took photographs. Nice legs. She ripped me off," Brown read, adding: "That’s the last date Tracy Tafoya was known to be alive."

Investigators have said Naso might have used his then-wife’s panty hose to strangle Roggasch, a prostitute whose 1977 murder went unsolved for decades.

Colon’s decomposed body was found near Port Costa 1978 by a California Highway Patrol officer in Contra Costa County. Authorities have said DNA evidence collected from her fingernails could tie Naso to her slaying.

Authorities previously said Naso was being investigated for possible links to New York’s "Double Initial Murders" of three girls in the early 1970s.

However, no charges have been filed.