Days before the premiere of "The Curse of Oak Island" season 5, more new discoveries are revealed in the show's trailer which excites its fans and viewers. Aside from the treasure chest, coins, and other findings, the team also discovered a cryptic historical letter. Evidence also points out that someone was in the island years ago.

Rick Lagina examined a mysterious letter which is found in their huge dig. In the trailer, said letter appears after Marty Lagina's son Alex is seen walking in a room while carrying a chest. An image of the letter is shown which appears to be hand-written by someone called Robert.

It also mentioned a guy named James.

It talks about a bond and a sum of money. Aside from that, it mentioned Philadephia and a return to Baltimore. Will this letter help the Lagina brothers figure out where the treasure [VIDEO] is? Or will this lead them to more new discoveries?

Lagina brothers think people were on the island

"The Curse of Oak Island" producer Jack Begley said that it is confirmed that was someone was on the island in 1600s. A pirate flag is shown as well as a 1652 Spanish maravedi coin that the team found in season 1. This season, Peter Fornetti and Gary Drayton are seen searching in the woods. It appears that they found another old coin from the dirt.

Rick said that with everything they found on the island, there are many what-ifs and possibilities. He added that they need to follow every lead. Aside from that, Alex Lagina is also heard saying that they hope to find any evidence of the treasure.

They also found a curved object from the dig and Rick said that humans put that there. Who were on the island? Were they the ones who buried the treasure?

The team is in full effort

"The Curse of Oak Island" season 5 shows that the Lagina brothers and the rest of the team are doing their best to find something that will help them discover the island's treasure. Besides the huge dig that they made using a crane, they also sent someone in the waters since a diver is lowered down with a camera with him. The Lagina brothers believe that they will find something there.

There has been non-stop activity on the island as the team continues digging. They work day and night which leads them to discover various items like the chest, an old coin, an old letter and many others. What else will they find for this season? Will they be able to get a big lead to the treasure? Fans will soon find out as "The Curse of Oak Island" season 5 airs in Nov. 7 on History.