DETROIT - Federal agents spent days using a pneumatic chisel to separate frozen clumps of heads, arms, legs, organs and torsos found in a Detroit warehouse in 2013, an FBI investigator testified Friday in the fraud trial of a body broker.

In some cases, body parts were found in ordinary beer coolers, Tupperware, paint cans, 50-gallon drums and even in a refrigerator next to ingredients for sandwiches, said FBI Agent Leslie Larsen during the opening day of the federal criminal trial for Arthur Rathburn.

Rathburn, 64, of Grosse Pointe Park, and his ex-wife Elizabeth Rathburn were accused of operating a body broker business named International Biological Inc. and fraudulently misrepresenting its unusual products -- human body parts.

They purchased disease-infected bodies at a discount and failed to disclose infections to customers, according to federal investigators. Sepsis, HIV and hepatitis were among the infections that U.S. attorneys say Rathburn failed to disclose.

Customers would rent body parts that originated from dead people who donated their bodies and organs to science. The cadavers were dissected and displayed at "primarily seminars," U.S. Attorney John Neal said during opening statements.

Arthur Rathburn is charged with 13 federal crimes, including nine counts of wire fraud, a count of illegal transport of hazardous material and two counts of making false statements to a public official.

Elizabeth Rathburn pleaded guilty to a count of wire fraud and agreed to be a witness against her ex-husband for the government.

The court testimony from the FBI agent Friday, Larsen called the warehouse "filthy" as she described photos she and her colleagues took while at the warehouse when it was raided in December 2013.

There were piles of dead flies and other insects -- 10 to 20 piles, she estimated, bodies that had frozen together requiring a crowbar to separate and various power saws used to dismember cadavers in what she called the "cutting room."

There was no running water nor operational restrooms. The FBI rented portable toilets they used while conducting the multi-day investigation at the warehouse.

While each of the 16 jurors were provided copies of numerous gory photos, which they kept in manila folders, U.S. District Judge Paul Borman forbid attorneys from displaying them on the large overhead screen. Other, less gruesome images were projected onto the screen.

The U.S. government claims Rathburn ignored basic industry standards that he knew customers expected his company to maintain, and intentionally withheld information about diseased bodies in order to secure business -- and widen his profit margin.

The government says its case centers on three cadaver rentals to seminars that Rathburn's company supplied.

In one case, Rathburn provided a cadaver for a dissection at a 2012 American Society of Anesthesiologists seminar in Washington D.C., according to court testimony from Dr. Kevin Vorenkamp, who signed the agreement with Rathburn.

Court records entered into evidence by assistant U.S. Attorney Timothy J. Wyse included an invoice sent to Rathburn by the Biological Resource Center of Illinois, the entity that originally received the donor's cadaver.

According to the invoice, Rathburn agreed to pay $5,000, but he received a $3,500 credit because the body had tested positive for HIV and hepatitis B.

He received lab results for the same body in 2011 that revealed the same, based on another document presented to the jury.

None of this was disclosed to Vorenkamp when he agreed to pay Rathburn for the cadaver, he testified. Vorenkamp said the agreement required that the human tissue was screened for HIV, hepatitis and other diseases.

Had he known of the infections, Vorenkamp said, he never would have accepted the cadaver, due to health concerns.

While the agreement said the cadaver had been screened, it added that the biological tissue should "still be treated by the service user and its research participants as if such materials may be infectious" and that "the service provider expressly disclaims any liability should any anatomical material prove infectious."

Rathburn came to the government's attention when he arranged for a human head to be flown to Chicago from Tel Aviv in 2012. He'd provided the severed head to a dental seminar and it was being returned after the seminar concluded.

It was, however, intercepted by U.S. Customs agents. Assistant U.S. Attorney John Neal, during opening statements, said the head was infected with sepsis and was not shipped in accordance with bio-hazard requirements. Instead, it arrived in a trash bag packed in a cooler with pooled fluid.

The government claims Rathburn lied to officials, telling them the fluid, which turned out to be human, was actually Listerine. He also lied to Customs officials when he said the head had been embalmed, a process of preservation and sterilization, according to prosecutors.

Rathburn's attorney, James C. Howarth, said this case should never have become a criminal matter, and was at worst a contractual dispute.

He also says the office-related aspects of the business, including written agreements and decisions about which body parts to ship to customers, were handled by Rathburn's ex-wife, Elizabeth Rathburn.

Trial is scheduled to resume Tuesday, and testimony is expected to run through at least Feb. 7, based on an online court court schedule.