A friend is trying to recall the author of a series that she liked but hasn't read in a several years. Here are the clues:the  protagonist is a policeman. He lives in a house on a canal (maybe San Francisco?), his wife is also a police-type who heads a department, and they have a son who is in college. One of the police informants was killed, and the protagonist and his wife adopted the deceased informant's daughter.

Does this sound familiar to anyone?

My friend suddenly remembered the author--Bill Pronzini!! She was looking for his Nameless Detective series that is set in San Francisco. Thanks to everyone for their help!

I can rule out San Francisco since there are no canals there. No real canals in the Bay Area either --- there is the San Francisco Bay and the ocean, however. At least nothing called a "canal."

When you reach further outside the Bay Area -- there is the Delta, which I suppose could appear to be canals if one wasn't familiar with the area. I can't think of any mysteries set in that area, however. I'd be all over them if I knew about them.

Other than that, I can't really think of what it could be.

The part about adopting the daughter could almost be the Pray series by John Sandford, but his wife is a doctor and they don't have a son in college. Oh, and they live in Minnesota. Good series though--your friend may like it.

I thought it might be a Lawrence Sanders series with Francis X Delaney but I don't remember the adoption.  He lived near water but I'm not positive it was a canal.