A trail is underway in the case of a New Jersey construction worker who is being sued by his former co-workers after cashing in a $38.5 million lottery ticket.

Americo Lopes and five co-workers participated in a weekly lottery pool starting in 2007 where they worked at Berto Construction, according to the New Jersey Star-Ledger.

Each participant contributed $2 to the pool and Lopes would buy the tickets. Lopes also played the lottery independently from the pool.

On November 10, 2009, two winning Mega Millions tickets were claimed from a $77 million jackpot, one of which Lopes had, leaving him with $38.5 million. He chose a lump sum and received $24 million after taxes.

Two days later, Lopes allegedly told his boss he needed foot surgery and would be back in the spring. In March, he said he had won the lottery and would not be returning to work, reports the Star-Ledger.

After co-workers were initially happy for Lopes, co-worker Candido Silva Sr. discovered online the date of Lopes win matched a date the group pooled tickets.

"I froze," Silva told the Star-Ledger. I didn't want to believe that these were the dates we were playing together."

A lawsuit was filed in April 2010 by Silva Sr. accusing Lopes of fraud and asking for $4 million for each pool participant.

The trial started Tuesday in Elizabeth, N.J., and is reliant on witnesses — there are no copies of the alleged tickets.

The defense argued Lopes purchased the ticket by himself, not with the group and the dates are a coincidence. The co-workers attorneys argued Lopes allegedly never received foot surgery and never told co-workers he won, reports the Star-Ledger.

For the co-workers to be successful, they are going to have to establish what the normal situation was for purchasing tickets, Florida lawyer Tom Culmo told ABC News. Culmo has experience in lottery cases and is currently handling one right now.

"I would look historically in what those people would contribute towards the pot to purchase the tickets normally done in the past, if it was routine for the lottery tickets to be purchased in a particular place and particular day," he said.

Culmo said his approach would be to demonstrate that it wouldn't make sense Lopes was buying the ticket for himself that day, and getting sworn statements from those involved in the situation and store workers where the ticket was purchased about the routine.

"Ultimately, the result will be determined by a jury or a judge...who decides who will win, will look at the entirety of the situation, what really makes the most sense here," he said. "If they are all believable people and their stories all match and mesh, the person who is trying to say I'm not sharing, anybody looking at that scenario, that doesn't make a lot of sense."

Candido Silva Jr., Carlos Fernandes, Daniel Esteves and Jose Sousa are also listed on the suit on the plaintiff side, according to New Jersey court records.

The New Jersey State Lottery offers guidelines for participating in office pools to avoid discrepancies, suggesting players get the names and phone numbers of everyone involved, especially individuals in charge of purchasing tickets as well as who is holding them. Also know where your tickets are being purchased and get copies of your tickets prior to the lottery drawing, including the serial numbers on the back of the tickets.

The current Mega Millions jackpot in New Jersey is $200 million.