When Jim Stauffer's elderly mother Doris passed away at the age of 74, he decided to donate her brain to science. Doris had suffered from dementia, and he wanted to help find a cure for brain diseases such as Alzheimer's.

The Biological Resource Centre (BRC) in Arizona seemed like the right option. It was even suggested to him by a nurse. Ten days after gifting his mother's body for medical research, he received her cremated remains.

It wasn't until a Reuters journalist called him, years later, that Stauffer discovered the truth. His mother's body had never been used for brain research. Instead, it had been sold to the US Army for blast testing, despite the fact that Stauffer had explicitly forbidden this type of research in a signed consent form.

"There was actually wording on this paperwork about performing this stuff," Stauffer told ABC 15 in Arizona. "Performing these medical tests that may involve explosions, and we said no. We checked the 'no' box on all that."

If you've registered to be an organ donor after your death, that's not actually the same as donating your whole body to science, which is an important distinction people aren't always aware of.

And there are many reasons why people donate their bodies, or those of their loved ones, to science. For some, it's about cutting financial costs on a funeral; for others, it's about furthering education, medical research, or repaying a gift.

Depending on the institution that receives the body donation - whether a medical school or a research centre - the remains can be used for myriad scientific and educational purposes. In fact, such body donations are absolutely vital for medical students learning anatomy and practising surgical techniques.

In other cases, there is also the hope - or an explicit understanding - that tissue from the body donation will be used for medical research purposes, whether it's to discern more about various types of cancers or, as in the case of Stauffer's mother, to investigate the genetics of Alzheimer's disease.

Unfortunately, in the United States, when it comes to the respectful use of cadavers for research, this last selfless act is too often based on trust alone.

If you don't approach a respected medical school or university but end up donating through the private sector, recent investigations have revealed the risk of donations ending up in the possession of a corrupt for-profit business that ignores the consent forms you've signed, and treats the bodies with little respect.

In 2016, a lengthy investigation by Reuters threw the spotlight on a "little-known and virtually unregulated industry": America's body trade.

"These businesses, which call themselves non-transplant tissue banks, are also known as body brokers," the investigation reads. "The operations can resemble meat-packing plants. At BRC, body parts from heads to fingernails were harvested and sold."

Unlike the organ and tissue transplant industry, which is highly regulated, these for-profit companies are subject to very little oversight.

For example, while transplant organs are not allowed to be sold in the US, no such federal law exists for cadavers or body parts being used in research or education. In fact, it is currently legal in most US states to sell donated human bodies for this very thing.

In 2016, Reuters found out that including Stauffer, more than 20 dead bodies donated to the BRC were sold and used in military blast experiments. In many cases, consent for this type of research had not been given, and others had no idea what they were getting into.

"These agreements are often written in technical language that many donors and relatives say they find hard to understand," explains the Reuters investigation.

"The documents give brokers the right to dismember the dead, then sell or rent body parts to medical researchers and educators, often for hundreds or thousands of dollars."

Today, 33 people, including Stauffer, are suing the centre for using their loved ones' remains without dignity or respect, according to the Arizona Republic.

It's not clear how many other corrupt body brokers are out there, but BRC is not alone. As part of the Reuters investigation, it was found that a body broker in Portland, called MedCure Inc, had sold or leased roughly 10,000 body parts from US donors annually, shipping about 20 percent of them overseas.

After the BRC case made headline news a few years ago, Arizona's governor tightened state laws so that body brokers must be licensed and regularly inspected, with a medical doctor at hand to supervise company practices. These regulations, however, will not be enforced until next year.

Body donations are crucial to medical research, but until there are strong laws protecting donors nationwide, those who wish to gift their bodies to science should take extra care to choose the right place and read the consent forms extremely carefully.