"Roses and a dead body?" Anna wrinkled her fine nose. "I don't see the connection."
"And they came from Paris," I said. "How did it end up here?"
"Yeah. It's a six-hour drive. What kind of nut would travel that long to deliver flowers to a corpse?"
"Maybe the person was already here?"
Carl held up his palms. "Ladies, ladies, slow down. Let's look at the questions one by one."
There are three people in this scene: the narrator, Anna, and Carl. I wrote something like this a while back, but some readers complained that they couldn't tell who was talking in paragraph three (Anna) and four (narrator).
How should I format (e.g. by adding dialogue/action tags) those paragraphs to remove ambiguity and still keep them fast paced?