A California man convicted of the murders decades ago of four women whose names and surnames bore matching initials has been sentenced to death.

Joseph Naso, 79, was found guilty last month in the so-called "Alphabet" killings of Roxene Roggasch, Carmen Colon, Pamela Parsons and Tracy Tafoya.

The bodies of the four strangled women, who worked as prostitutes, were dumped in rural areas in the 1970s and 1990s.

In 2009, probation officers in Reno, Nevada, carried out a routine firearms search of Naso's home and Naso was prosecuted after police found evidence in his home.

A journal with detailed descriptions of rape and violence toward underage girls and women was also uncovered.

The report stated that Roxene Roggasch, 18, and Carmen Colon, 22, were killed in the 1970s. Pamela Parsons, 38, and Tracy Tafoya, 31, were killed in the 1990s.

Naso, a former photographer, represented himself at his trial in Marin County, telling the jury he was "not the monster that killed these women".

However, Deputy District Attorney Dori Ahana argued for the death sentence, presenting the jury with macabre photographs of the lifeless bodies, and in September the jury recommended he be sentenced to death.