A backpack stuffed with $49,400 in cash seized by authorities at Boston Logan International Airport last year is part of a legal battle over whether the money can actually be kept by the government.

The government claims the money was part of illegal drug sales, but the owner of the cash and his lawyers say authorities have no proof other than suggesting a criminal act was involved.

Carrying a large amount of cash isn’t evidence of illegal activity, the man’s lawyers argue.

The issue over the legality of the proposed seizure of the cash began on May 1, 2018, when Robert N. Kenny headed to Logan to catch a flight to San Francisco that night, according to a civil filing in a federal court in Massachusetts.

Details of the discovery and seizure of the cash are contained in an affidavit filed by U.S. Drug Enforcement Special Agent David X. O’Neill.

The affidavit described the following events:

Massachusetts State Police Trooper John Banik was advised that Kenny arrived at the Transportation Security Administration checkpoint in Terminal B with a large amount of cash in a carry-on bag.

Kenny had a North Carolina license with him.

A TSA agent noticed several bundles of cash - 1,950 $20 bills and 208 $50 bills for a total of $49,400 – was inside Kenny’s backpack.

“The odor of fresh unburnt marijuana was on the currency,” O’Neill wrote. “Based on my training and experience, the packaging and the smell of the currency is consistent with proceeds from the illegal sale of narcotics.”

Kenny was taken to an interview room. Banik and Logan Airport Task Force member Detective Lt. Thomas Coffey soon joined him.

Kenny, they told him, wasn’t under arrest and could leave any time. The investigators wanted to talk about the cash. Kenny agreed to talk.

Sitting with the investigators Kenny described himself as the chief executive officer for Royal Supply, a San Francisco company. Kenny handed the investigators a business card.

A check of the company’s website shows the slogan, “We’ve got what you need, except the weed.”

“Our company was founded by a couple of long-term friends driven by the desire to play an integral role in a rapidly expanding and evolving cannabis industry,” the company states online. “Our mission is to be a leader in the product packaging marketplace.”

The company, according to the website, serves customers across the country.

Kenny explained to the investigators his company is a product packaging and marketing company focusing on food and other items. Fourteen people worked for the company at the time of the interview with an office in San Francisco and a warehouse in Stockton, California.

A quick check of the inventory for sale shows “joint tubes”, vape supplies, glass containers, pill vials and various other containers for sale.

Kenny headed to Boston to collect money for services provided. He arrived in Massachusetts at 5:40 a.m. on May 1, 2018, and planned to fly back to San Francisco later that night.

“When asked where he traveled to meet his business contacts, after an extended pause, Kenny said that he believed he went to Bellingham, Massachusetts after requesting a ride from Uber on his cellular telephone,” O’Neill wrote.

The man he met was named, “Chris”. Kenny’s company provided “Chris” product for his company. Kenny was unable to give any more details about Chris or his company.

Investigators say “Chris” is actually someone known to the DEA as a suspected marijuana trafficker. His last name was omitted from the investigator’s affidavit.

“Chris”, according to O’Neill, was caught with $84,000 on August 14 in Massachusetts. He admitted the cash was being used to buy pounds of marijuana. The government seized the cash. The U.S. Attorney’s Office filed a notice of forfeiture in the matter.

The investigators say Kenny’s cell phone also showed he had been in contact with another person in Bellingham, a person who had been busted for marijuana cultivation and distribution.

The reason for carrying the cash was simple, Kenny explained. There were no branches for the bank he uses in Massachusetts.

Kenny didn’t want to talk about why he would be paid in cash by someone, O’Neill wrote. He stated his company produced “paper and plastic” products.

As the investigators spoke with Kenny, O’Neill checked out the company and discovered the motto and the marijuana packaging supplies for sale.

The customer service number – 1-888-PACK-420 – was an obvious reference to pot, O’Neill wrote.

Kenny didn’t want to talk about his business any further, authorities said.

The investigators told Kenny he was free to go and fly back to San Francisco. The cash, however, that was staying in Massachusetts, the investigators told Kenny. He declined an offer to get a receipt for the money at the State Police Logan Barracks.

The cash was taken to the barracks. Trooper Christopher Coscia and his drug detection dog, Felix, showed up.

The money was hidden in an office. The trooper and his dog were sent in to search the room.

Felix found the cash hidden in a drawer, O’Neill wrote.

Authorities then checked the financial records for Royal Supply. Twenty-nine cash deposits, totaling $159,852, were conducted from Dec. 8, 2017, to April 18, 2018, O’Neill said.

The cash deposits were odd to police, considering the company doesn’t have a physical storefront.

O’Neill said the cash was seized because authorities believe it is cash involved in illegal drug sales.

In a statement filed in federal court, Kenny said the cash was payment received for “non-contraband goods.”

In a motion to dismiss the forfeiture, Kenny’s lawyers said the government has no proof to show the cash was involved in illegal drug sales.

Kenny never tried to hide his identity or travel plans, the lawyers wrote in a December motion. Carrying a large amount of cash is not evidence of illegal activities either, they argue.

Even though Kenny wasn’t under arrest, he still answered investigators’ questions and explained why he was in Massachusetts, the motion said.

The smell of marijuana on the cash isn’t odd. The court system has recognized that U.S. currency is contaminated with narcotics, according to the motion.

“Here, the government has not alleged details of a criminal act that is linked to the defendant currency,” the lawyers wrote. “Instead, the government surmises that there is a nexus between the defendant currency and some unspecified predicate criminal activity by alleging Kenny spoke and/or met with an individual named “Chris”, a suspected marijuana trafficker, and another individual who the government alleges was ‘arrested on multiple charges involving cultivation and possession to distribute marijuana’.”

The Boston-based law firm representing Kenny did not return a call seeking comment.