The Iris Deception — Bernard Schopen

In this third Jack Ross mystery, the Reno private eye is hired by iris-eyed Patsy McLeod to resume a case abandoned as hopeless eighteen years earlier--the search for her missing teenage daughter Heather. This time, Ross's investigation leads him from a failed ranch in the desert north of Reno to Sacramento's porno film industry, from the Lake Tahoe homes of the wealthy and powerful to the cramped offices of Berkeley's activist community. On the way, he uncovers layers of deception, greed, corruption, sorrow--and murder.
Ross also encounters Martha Reedy, a Berkeley-based P.I. who is as dogged about finding Heather as Ross, but for different reasons. Both are used to working solo, but find their paths hopelessly intertwined.