Author is Parnell Hall writing under a pseudonym. Entertaining read; in the style of Perry Mason.
From the cover:
For an attorney with only one client, Steve Winslow isn't doing badly - the work is easy and he has the time to read Variety and remind himself how hard it had been to be a struggling actor.
Then the envelope arries. The $10,000 envelope, with the unsigned note.
Steve Winslow has just acquired his second client - and a load of trouble. Before he can figure out who sent the money, Winslow lands in the middle of a murder investigation . . . as the prime suspect!
Winslow will need all the help he can get to stay out of jail - help from his old college buddy turned private investigator; from his wise-cracking, mystery-reading super-efficient secretary; even from the very unhappy and uncooerative police.