harris's new warnings to migrants, don't come to america. and ahead of our exclusive interview the criticism she' facing why isn't she visiting the u.s. border with mexico our team at the border and deep inside guatemala. why so many here risk everything for the dangerous journey to america. also tonight, the fda approving the first new alzheimer's drug in nearly two decades. why it's so controversial. the new reveal from the justice department how it turned the tables on the colonial pipeline hackers to recover millions in ransom the arrests in the road rage shooting that killed a 6-year-old boy the battle in one of america's most expensive cities the idea some say to housing a lot more affordable. and billionaire blastoff the surprise announcement from amazon's jeff bezos. >> announcer: this is nbc "nightly news" with lester holt reporting tonight from guatemala city good evening from