Counterweight. The Tony Mandolin Mysteries, #3

When a leprechaun shows up at Tony's house looking for his lost niece, Tony's life becomes a lot more complicated. Tony Mandolin-Luddite private eye, technophobe, and the last guy in the Bay Area who still uses a rotary phone-gets dragged into the mess whether he wants it or not. The lost niece is not lost, and the leprechaun is no uncle, and then there is this pregnant werewolf... The trail leads through every unsavory section of the city and even the Pixies want in on the action, tricking Tony into being the one tasked to find their lost treasure, which turns out to be what every magical power in the city has its eyes on..
With an FBI Agent who acts like he's a cast member of the X-files, and creatures popping up demanding Tony give them the treasure, Tony has to find whatever it is before the demands turn into war.