flared up again yesterday.

And in Georgia, a Delta Airlines jet returns safely to Atlanta this morning after experiencing what the airline called an engine issue shortly after takeoff. Well, one passenger reported seeing flames coming from the side of the engine.

And talk about some diploma disappointment. More than 200 recent high school graduates in Plymouth, Massachusetts, will be getting new diplomas because of spelling errors. The company who printed them apologized for the, quote, "human error", and quickly reprinted them.

The head of the ATF may resign today after operation called "Fast and Furious" turned deadly for one of its own. "Fast and Furious" was supposed to take U.S. agents right to the Mexican drug cartels but here's the problem. The guns were lost. And some of those firearms turned up at the scene of a shoot-out that killed U.S. Border agent Brian Terry.

Brian's attention to detail had ensured that all the Christmas gifts he had meticulously selected for his family had already been bought and sent in the mail prior to his arrival. Brian did ultimately come home that Christmas. We buried him not far from the house that he was raised in just prior to Christmas day.

Drew Griffin of CNN's Special Investigations Unit has been chasing this story.

So, I mean, I guess the first question off the bat, what was the government thinking, putting weapons into the hands of cartel members?

You know, it's such a stupid and absurd program it's hard to imagine anyone ever thought it was a great idea. But here was the idea.

The problem was guns were going to fuel the violence of the cartels in Mexico. So the ATF officials thought if we could just track these guns and see where they're going, maybe we can arrest the cartel leaders who are using these guns.

The problem was they just allowed illegal gun purchases to be made in the U.S. and then the guns walked across the border. Literally walked across the border. AK-47s. There was no way to track them once they were in Mexico. And Mexico had no idea that the U.S. government was doing this. So, Mexico wasn't involved in any part of this to track these guns.Thereby, the only way you could find out where these guns went literally were to pick them off dead bodies at crime scenes.

Unbelievable. So, we're not just talking about the head of the ATF, but there had to be a change of command issue, too.

Because the sources I've talked to, the ATF agents who watched these guns go across to Mexico and protested it said this was a major operation.

So, there were ATF agents that said, wait, this is wrong.

Absolutely.

So, there were agents that stepped up and said this is

I talked to one ATF agent literally watched a straw buyer undercover, and go into an Arizona gun store and buy 10 AK-47s, called his boss, do we arrest him now? Do we arrest him now? Do we arrest him now? Let's get him, let's get him, let's get him.

The answer was, no, just watch where he goes.

So

And he went across the border.

So, more people here are going to lose their jobs. It's not just the head of the ATF.

Well, the question they have in Congress. And really, this is being pushed by Darrell Issa, the Republican congressman in the House, House Oversight Committee. He wants to know who at the Department of Justice knew. Now, it looks like Kenneth Melson, the acting director of ATF, is going to take the political fallout for that.

Will it stop there? There's a Justice Department inspector general's investigation going on. Eric Holder, the attorney general, insists he didn't know about it. The people in Congress say that's really hard to believe, because this was such anintricateand involved and expensive program to pull off.

And because, at the time, even though we now looking back on it, say this was absurd, the ATF was really excited about this. They thought they were going to score some big name arrests once this operation was over with.

We are going to stay, obviously, following this and see if, indeed, that resignation comes today.

Drew, great work. Thanks.