Near the beginning, when the team first reviews the case, Penelope says that one of the victims was found near a cable car stop in San Francisco's Mission District. Cable cars don't go into the Mission District; they travel through the financial district, up to North Point, and down California Street as far as Van Ness Street.
Reid points to a specific section of a map of San Francisco when he tells Morgan to focus on the Mission District, but Reid isn't pointing to the Mission District.
At the end, the unsub states that Vincent van Gogh sold two paintings while he was alive. Van Gogh only sold one painting during his lifetime.