Dangers on a Train (A Reed Ferguson Mystery, Book 20)

Denver
private investigator Reed Ferguson's off-duty ride on a Denver
light-rail train turns deadly when he retrieves an envelope accidentally
dropped by one of the commuters, a young college student.  The envelope
contains a picture of a body, but who is it? And isn't that blood near
the person's head? 

Reed's curiosity gets the best of
him, and he feels compelled to find the student, who tells a bizarre
story of a stranger hiring him to pass the envelope to a woman on the
train. The student doesn’t know who she is, or what was in the envelope.
And now the stranger is after him. As Reed searches for the stranger on
the train, he soon discovers the identity of the body in the picture,
and a number of suspects who have good reason to want him dead.

To make matters worse, the stranger has his sights on Reed …