By Chris Hansen, Dateline Correspondent

We'd been hearing complaints from senior citizens and government regulators across the country about the tactics some insurance salesmen are using to sell certain investments to retired folks. I'm a long ways off from retiring, but it's an important subject to me because my mom's close to that age and my aunts and uncles are already there. Given the turbulence we've seen on Wall Street, it seems like everyone is re-evaluating or repositioning their investments and would like to have their money in a safe place. And that's what a lot of salesmen are pitching these days.

The investments are called equity-indexed annuities. They may be appropriate for some, but not for everyone. Why are so many people trying to sell these to retired folks? Simple: that's where the money is. Seniors control more than $15 trillion in today's economy and for the salesmen, these annuities pay healthy commissions.

Dateline decided to use hidden cameras to find out what salesmen were really saying or not saying to seniors when peddling these investments. We attended some of those "free lunch" seminars put on for potential clients, classes where salesman are taught the tricks of the trade. We wired some houses in communities where a lot of retired people live, so we could see the one-on-one pitch play out in real time.

What we found in many cases was remarkable. Some salesmen are being trained to scare the elderly into buying certain investments. In our hidden camera homes, we saw that some agents were not disclosing how long the senior's money would be tied up, in some cases longer than the investor would live. We also saw some salesman not disclosing details about surrender penalties that would have to be paid if the senior had an emergency and had to access their money.

In order to carry out this investigation, though, we needed the help of some senior citizens who would invite salesmen over to hear the pitches. In Alabama, we met a 77-year-old semi-retired lawyer named Leon who fit the bill.

But we also needed help in Arizona. I had just seen my aunt Alice at a funeral in Chicago. She had come up from Arizona, where she lives part of the year. We had a nice chat and I expressed my condolences for her husband, my uncle Charlie, who had also recently passed away.

A few weeks later I wondered if Alice might be the perfect choice to help us in our investigation. After consulting my mom, I reached out for Alice who ultimately agreed to be a part of our story. She was perfect because she was exactly the type of person some salesmen seek: retired, widowed and in possession of a retirement nest egg.

She asked the right questions and as you'll see in our story she presents herself pretty darn well on camera. Now if I can only get the rest of my family working on my stories.

Click here for the full story and video of 'Tricks of the Trade.'

Click here to read more of Chris Hansen's behind-the-scenes looks at his investigations.