A Body in My Office by Glen Ebisch

He's not at all happy to hear he's being replaced by a man he doesn't like.  When he gets back to his office, the other guy is already moving in.  And the thing that makes him angriest is when he finds the man has dropped his wife's picture and the glass is broken.  She died in a car accident three years ago and he loses his temper.  He picks up the trophy the other man has placed on his desk and throws it against the wall and storms out...

Williams and Whiting and Edelweiss let me read this book for review (thank you).  It has been published, so you can grab a copy now.

After hanging out in the parking lot for about half an hour, he calms down.  However, when he goes back to his office to get his box of belongings, the other man is dead.  And the trophy was what killed him...

He talked to a couple of people while outside but not enough to cover the whole time.  He had time to go back for murder.  So he becomes a "person of interest" in the case.  When the police aren't able to get enough information about the dead professor, they let him help.  That's what he wants to do anyway.  Being retired is boring.  He also likes the female cop.  Then he goes to the house of the professor's wife with the girl carrying his baby to talk to the wife.  She's dead also.  Finding two corpses doesn't make him look more innocent.

As he tries to help with the case, he finds out things about himself and his relationships that is shocking to him.  The killer was closer to him than he could imagine.  The good news is that he is going to date the female cop, so there's hope for the future.  Sometimes knowing the truth hurts.