X by Sue Grafton

After completing the quick and straight forward job of providing the contact details of a son who had been put up for adoption as a baby 32 years ago and who has recently been released from prison, Kinsey Millhone finds that she has been paid for the job with marked notes.  The client has now vanished and the contact telephone numbers provided are out of service. She sets up her own investigation to find out who the client really is and why she wanted the details. 

At the same time she is also helping a widowed friend to go through paperwork left by her murdered husband, PI Pete Wolinksy, who was an old associate of Kinsey's.  They find a hidden parcel which needs to be delivered and some old notes from an investigation Pete was undertaking.  Kinsey picks up the investigation and discovers links between a number of women and a very dangerous sociopath. 

V is for Vengeance by Sue Grafton

Whilst out shopping one day PI Kinsey Millhone witnesses a lady shoplifting.  She helps the store to apprehend her.  Kinsey is then almost run over in the car park by a second woman who may have been an accomplice. 

A few days later Kinsey reads in the local paper that the body of Audrey Vance has been found at a local suicide spot.  There is a photograph of Audrey, she is the shoplifter.  

Kinsey is approached by Audrey's fiance and asked to look into her past as he is convinced that she would not have killed herself and that she would not have been shoplifting.  

As Kinsey starts to investigate she finds evidence to indicate there may be a large criminal organisation operating locally in which Audrey has been involved.