"We must look everywhere," he said, turned around and then added, "Let's start here."
Should the last sentence (Let's start here) start with lower case or upper case? Since the speech is interrupted, it probably should start with the lower case. However, it is a new sentence, not a part of the interrupted one.
I understand these examples:
- "If you want my opinion," John said, "this is ridiculous."
("If you want my opinion, this is ridiculous." — the whole sentence is interrupted in the middle, hence the lower case in the second part.)
- "He only had one drink," the bartender said. "Now look at him."
("He only had one drink. Now look at him." — two sentences, the second one starts with upper case.)
But if it is a combination of the two, what should one use?