Watch the special expanded series finale online now.
Authorities say the man behind one of the worst mass shootings in US history was a 20-year-old whose mother worked at the school and whose brother has told them he had a history of mental problems. NBC's Pete Williams reports. (TODAY)
In California, the average price of gas is up 36 cents in a week, to $4.49. And on Friday, some stations neared $6 a gallon. NBC's Kristen Dahlgren reports. (Nightly News)
Haitians this morning are assessing the damage from Tropical Storm Isaac's landfall on a vulnerable country still recovering from the earthquake of 2010. (TODAY)
A late-night earthquake rattled homes — and nerves — across Okla. last night. NBC's Lilia Luciano reports.