6:20 p.m. ET: EXCLUSIVE: The United States will take "all necessary and proper steps" needed to deal with the ongoing hostage situation in Algeria, Defense Secretary Leon Panetta told ABC News' Martha Raddatz in an exclusive interview, although he cautioned that American officials fear the information coming out of the African country is "pretty sketchy."

Read the developing story HERE and get the latest from ABC's Martha Raddatz tonight on "Nightline."

Credit: Getty Images

3:58 p.m. ET: UPDATE: Jodi Arias lulled her ex-boyfriend into a vulnerable position by having sex with him and taking sexy photos of him in the shower, catching him off guard when she attacked him with a knife, prosecutors argued today.

Read the full story HERE. Last night, "Nightline" reported on the explosive Arias recordings played in court. Give a listen HERE:

2:24 p.m. ET: Nev Schulman, the star and creator of the MTV show "Catfish" that follows Internet dating hoaxes, has reached out to Notre Dame football star Manti Te'o and offered to help solve his girlfriend hoax.

".@MTeo_5 I know how you feel. It happened 2 me. I want 2 help tell ur story & prevent this from happening to others in the future. Lets talk," Schulman tweeted to Te'o.

Read more HERE and watch the full story on "Nightline" TONIGHT

Credit: ABC News/AP Photo

12:48 p.m. ET: And now of course 'Te'oing' - people putting their arm around air and saying it's their fake girlfriend - is now a thing. And the Internet is going wild with memes like this:

Credit: photobucket.com

See much, much more HERE

12:25 p.m. ET: DEVELOPING: Notre Dame's star linebacker Manti Te'o faces a problem bigger than any running back he's had to bring down.

As the elaborate hoax about his dead "girlfriend" unravels, many questions remain to be answered, chief among them whether he was complicit in promoting the dramatic story of his girlfriend's death from leukemia. Te'o may soon be forced to tackle those questions himself.

Read the story as we update it HERE

Credit: Mike Ehrmann/Getty Images

11:45 a.m. ET: BREAKING: The Algerian government has reportedly mounted a military operation to rescue dozens of hostages, including Americans, being held by an al Qaeda-affiliated group at a natural gas plant in Algeria.

Follow our updates HERE

Credit: SITE Intel Group/AP Photo

10:04 a.m. ET: Miss us last night? Catch up on the latest "Nightline" episode during breakfast or maybe your lunch break today.

We listened to the explosive recordings played in court at the Jodi Arias murder trial:

Spoke with a controversial Bikram yoga guru who has built a multi-million dollar empire:

And traveled to "Secret Brazil," where we explored the hidden corners of South America: