I think she said "Did you see" or is it.. "Were you watching?"
"Were you watching?" would indicate a past progressive tense, closer to 見ていました?, whereas her statement here, 見ました?, is strictly a past tense phrase. And since "did you watch?" doesn't quite sound right for this context, we end up at "did you see [them]?" And from the ominous black background, I don't think Shiki will be going off our reply for her next action.