Produced by WBUR and the Boston Globe.

These are works of the civilization that are so important to remove them as to remove a piece of our civilization.

They came in and they turned so I could see them. I could see that they had hats, coats, badges, and they look like cops so I've blessed them the rest of the way into the music.

I remember feeling like I needed to prepare myself for death if it ended up coming to that.

If something is not right, it's almost as if there are two different heists because the ammo is different.

They're not similar except that they happen the same night.

The gates at the Isabella Gardner Museum will stay locked while authorities search for clues in the daring weekend heist.

Imagine all the mistakes you've ever made. Now imagine that just one of them, one lapse in judgment in one millisecond in time, hung over you for all of your days to come.

Imagine being known above all else for that one thing you did that you can never undo.

And now imagine that the going estimate for the cost of your mistake is upwards of $500 million.

Rick Abbott, who was manning the watch desk in the Gardner Museum at 124 in the morning on March 18th 1990, doesn't have to imagine any of this. He's lived it.

I haven't hidden it from anybody. Close to me, I haven't hidden it. No, I've told the story a billion times over the past 22 years.

At the same time, I'm not just advertising it normally either. It's not like when I go to get a job. I'm like, oh, hey, I opened the door on this route 22 years ago.

And they got robbed by $500 million. So hire me. You know what I mean.

Abbott has always maintained his innocence. And he says he's always been forthcoming about his decision to open the door the night of the robbery.

Even in his earliest exchanges with the first Boston FBI agent on the case.

And I said, well, what do you want to know? I will tell you anything. And I immediately spilled my guts.

That's why I didn't have anything to lose.

Rick Abbott has never been arrested for anything related to the Gardner Heist.

But he's also never escaped the suspicion of investigators who say that the men who robbed the museum had help from the inside.

That they knew their way around it and knew the police weren't coming. Their implication is that Abbott is the reason why.

Those investigators have never publicly named Abbott as a suspect. They won't even name him as one of the security guards on duty that night.

...