Jurors spent their first hours Wednesday afternoon formally considering the charges and evidence against four former Pilot Flying J employees accused of taking part in a multimillion-dollar scam to rip off some diesel fuel customers.

They reached no verdict. Deliberations in the federal case in Chattanooga are set to resume Monday morning.

It's a complex case involving multiple felony counts and many pieces of evidence, so the verdict is not expected to come quickly.

U.S. District Judge Curtis L. Collier told lawyers Wednesday afternoon it was possible the panel might not reach a decision Monday either.

Graphic of organizational chart for Pilot Flying J showing which top employees have been indicted or pleaded guilty in a rebate scheme as of July 24, 2017.

The group began hearing proof in the fraud trial in early November. The prosecution and defense wrapped up this week with closing arguments.

Former Pilot president Mark Hazelwood, Scott Wombold, a former company vice president, and sales employees Karen Mann and Heather Jones are accused of conspiring to cheat some fuel buyers of promised rebates.

The government alleges they -- and other now former Pilot sales employees -- took advantage of unsophisticated clients who didn't pay attention or didn't understand the kinds of rebates they were being promised and what they actually received.

Related: 5 Things to Know

Sales staff were motivated to offer promises but skimp on returns because they were trying to land and keep customers in the cutthroat world of fuel sales, the government alleges. You could also make tens of thousands of dollars in commission if you were really good, according to the government.

Closing arguments are set to start Monday, Feb. 5, and take all of Tuesday, Feb. 6.

Fourteen former Pilot Flying J employees have pleaded guilty, and some testified during the trial. They await sentencing by Collier.

Defense attorneys Rusty Hardin, David Rivera, Ben Vernia and Jonathan Cooper sought this week to persuade the jury that their clients either didn't approve or support rebate ripoffs or only took part because they thought what they were doing was justified.

On Wednesday morning, before deliberations began, the prosecution got a chance to respond to the defense. Assistant U.S. Attorneys Trey Hamilton and David Lewen represent the government.

Hamilton said the case could be summarized in three words: "Lies, deceit, fraud."

More: Diesel fuel sales brought big bucks for Pilot

"This isn't some kind of Mickey Mouse situation," he noted. "This is criminal fraud."

It amounted to about $56 million, according to Hamilton.

Pilot Flying J ended up paying a $92 million penalty as well as more than $80 million in civil settlements from clients who sued them over the fraud.

The prosecutor told jurors that the defendants may try to argue they didn't really know what was going on -- or didn't know it was wrong -- but the evidence is contrary.

He displayed for the jury numerous emails offered during trial that showed one or several of the four defendants talking about changing rebate rates or being part of email chains in which specific aspects of the scheme were discussed.

Some of the four also were secretly recorded by a Pilot employee and confederate for the government named Vince Greco. Recordings were made in 2012 and 2013 at sales meetings and at a gathering at a then vice president's home.

Managers including Hazelwood and Wombold inquired about deals that were going to be fraudulent and approved them in email responses, Hamilton said.

Hazelwood tried to tell his former assistant after he left the company in May 2014 that he didn't read weekly summaries of what the sales staff was up to. But Hamilton said evidence shows he did read them.

Former assistant Sherry Blake testified late last month her old boss expected her for years to prepare staff reports every Friday. According to the government, the reports included damning evidence of how direct sales personnel plotted to short-change some fuel customers.

Among the counts jurors are considering against Hazelwood is whether he tried to influence Blake's potential testimony, after an April 2013 federal raid of Pilot headquarters, by insisting to her he hadn't read the "trip reports."

Hamilton, as he wrapped up his remarks, asked jurors to consider what kind of a culture would allow such scheming to prosper. He told them the evidence indicated Hazelwood was a leader in that culture who sought to make even more money at the hands of unsuspecting customers.

The trial is being held in Chattanooga because of heavy pre-trial publicity in the Knoxville area, from which the case originates.

February marks the fourth month of trial, although there actually were only about 20 days of proof. The trial frequently was put off because of scheduling conflicts. No court was held over the Christmas and New Year's holidays.

Jurors are not working Thursday or Friday.