We have an explosive I-Team investigation.

We've discovered United States Postal Workers drinking and driving on the job.

Over the course of three months, our hidden camera investigation found some Milwaukee postal workers spending day after day, hour after hour in a local bar drinking alcohol and then driving off in postal trucks. You and I pay for those trucks.

We trust them to deliver our mail. And most Milwaukee postal workers do it in a safe, efficient manner.

Unfortunately, we found some workers apparently violating the public trust.

"Mike's, A Little Country" is a bar on near 26th and State Street. It's a small, neighborhood bar. It's a bar frequented by postal workers in uniform in the middle of the day.

Mike the mailman is postal employee we see in the bar on a regular basis.

Mike likes Miller Genuine Draft. In many of the shots captured by our hidden cameras, you can see a can of MGD in front of him.

We see mike in the bar day after day; always in the middle of the afternoon; always with his MGD.

Mike's big mail truck is often parked right out front.

And the people who live in this neighborhood notice.

Brian Mason passes the bar regularly. "I think it's terrible. I think it's terrible. I mean anybody that's going to drink and drive. There's too many little kids, too many families torn apart every day, every year." Mason told us.

And Mike does drink and drive.

On numerous days, we film him inside drinking and then outside driving off in his two ton mail truck.

Then there's Tom the mailman.

Tom prefers hard liquor.

On many days, Tom saunters into Mike's and saddles up to the bar in the middle of the afternoon.

Our cameras clearly catch him in uniform on numerous occasions. As our cameras roll, Tom takes down more than one mixed drink, as his United States Postal Truck sits outside. Our cameras catch Tom after an afternoon of drinking, climbing into his truck and heading back to work.

We asked Tom about his mid day boozing and cruising.

John: "Tom..."

Tom: "Yeah."

John: "Can we ask you some questions? Talk to me about why you're driving this around to the bar in Milwaukee."

Tom: "Is there a bar in Milwaukee that I'm next too?"

The answer to his question is, "Yes."

We see him at Mike's near 26th and State day after day.

John: "And then you stop and drink and get back in and drive it some more."

Tom: "No. No."

John: "We have video of you drinking. Are you going to tell me that's not true?"

Tom: "Yeah I am."

Really?

Here's Tom drinking.

Here's Tom drinking again.

Here's more of Tom drinking.

And here's Tom on the busiest postal day of the year, the Monday after Thanksgiving. And he's drinking.

John: "So you do not drive this truck to Mike's on State and then drink?"

Instead of answering us Tom got in his truck.

John: "Mixed drinks?"

Tom slammed the door as we continued to try to speak with him.

John: "We pay for this truck."

Jordan Sowdan is Milwaukee postal customer, "That's crazy if they're drinking and driving those kinds of trucks. I can't imagine."

Later that same afternoon we caught up with Tom again.

John: "Tom, we pay for this truck that you're driving around after you sit and drink."

Tom: "No. Our services do."

Who do you think pays for those services? We do every time we buy stamps or mail a package at a post office like Hilltop, where Tom works.

We asked Tom what his boss would think of our findings. Tom glared at us but wouldn't answer.

Tom didn't want to talk about the fact that day after day after day we saw him park his truck, go into the bar, have drinks, come back out and drive off in this truck. But his bosses? They had plenty to say.

Bob Cavinder is the Milwaukee Postmaster. "That is against policy. Anytime they are in uniform they are not to be consuming alcohol. I can assure you that this is not something that our employees make a habit of and I think it's something that, yeah we definitely have to take a look at."

On one day last month our helicopter actually caught Tom leaving the bar, hopping into his truck, and heading back to the mailroom to finish his day after consuming alcohol inside the neighborhood bar.

Cavinder saw our tape. "We need to look at what's happening out there with our employees, make sure they're staying on their routes." None of those routes include a cocktail at Mike's or any other bar.

Chris Russo lives in Milwaukee. "Unbelievable," he laughed. "Unacceptable. That's not cool. That's not right at all. No way."

We took one more crack at Tom, asking him, "Tom, why are you running from us, if you're not doing anything wrong?"

Caviner told us, "We'll also need to look at my management processes. Should we have done something better to make sure that things like this couldn't happen?"

We have learned a letter was sent out to all postal workers by the Milwaukee postmaster. It reminds workers that it is against policy to drink while in uniform.

That reminder may have come too late for at least a couple of workers; who we are told remain under investigation and could be fired.