It's a Mad, Mad, Mad, Mad Girl!, by Jeff Cohen (epub/Kindle)
It’s A Mad, Mad, Mad, Mad Girl! is a story adjacent to the Comedy Tonight Mystery series, but you don’t need to have read the books to get it. Elliot Freed, owner of an all-comedy movie theater, rushes to the hospital with his ex-wife, who is about to give birth to their first child. But Elliot sees something he isn’t meant to see in a storage closet and suddenly he’s hoping a mysterious resident attending to his child’s birth isn’t a murderer. . . .