ROCKLAND, Maine — Board members of one of the state’s largest fishermen’s cooperative had long been suspicious that their manager had been stealing from the business, but it was a tip to police from a former family friend that eventually led to search warrants and a felony theft charge against Robert E. Thompson of St. George.

The allegations contained in court records include that truck drivers from a southern Maine seafood dealer would turn over envelopes filled with cash to Thompson for lobsters skimmed from the cooperative.

The details of the investigation into the alleged theft of more than $10,000 from the Spruce Head Fishermen’s Cooperative were released Friday when a 90-day impoundment of the police reports contained in court records was lifted.

Thompson, 51, was arrested on Oct. 3 and charged with felony theft from the cooperative on Spruce Head Island in South Thomaston. While felony theft in Maine is defined as anything greater than $10,000, police records indicate that the theft could involve much more money.

When police raided Thompson’s home on Oct. 3, officers seized more than $20,000 in cash, computers and all his financial records, according to records filed in Knox County Superior Court.

Thompson — who had been the wharf manager for the cooperative for approximately 20 years — is free on $100,000 surety bail.

The unsealed affidavit stated that members of the board of directors of the cooperative met on Jan. 20, 2012 with Knox County Chief Deputy Timothy Carroll and Lt. Detective Reginald Walker to voice their suspicions about Thompson. Cooperative board member Casey Morrill said he had spoken to a lobsterman in Harpswell and that this lobsterman’s son was a truck driver for a southern Maine seafood dealer. The lobsterman told Morrill that the son said he dropped off large amounts of cash to the Spruce Head cooperative’s manager, according to the affidavit.

Thompson’s job included managing the buying and selling of lobsters. The southern Maine seafood dealer, which the Bangor Daily News is not naming because it has not been charged with a crime in connection to the case, was one of the the companies that bought lobsters from the cooperative. The cooperative ships 2 million to 3 million pounds of lobsters each year and the southern Maine dealer buys about two-thirds of those, according to the affidavit.

There are 56 lobstermen who sell to the Spruce Head cooperative and are part owners of the cooperative.

Morrill and board members David Cousens and Robert Baines also told the sheriff’s office that Thompson had been living beyond his means.

“Baines, Cousens and Morrill told Lt. Walker that they have suspected Thompson to be stealing from the Co-op for several years because they all see he spends so much money and the expenditures outweigh his income from the Co-op,” the affidavit states.

Thompson was being paid $60,000 per year by the co-op, according to the police report.

On Feb. 3, Lt. Walker met with an informant, who is not named in the affidavit, who provided first-hand knowledge of the alleged illegal activity by Thompson, according to the affidavit. The informant wants to remain confidential out of fear for personal safety, according to the affidavit.

The informant had known the Thompson family for a decade but had stopped having daily contact with them in 2009. The informant has no criminal record nor pending charges but had been addicted to opiates at the time of knowing the Thompsons, according to the affidavit. The informant also had been involved in litigation against the Thompson family, the affidavit states.

The informant had witnessed envelopes of cash being dropped off to Thompson by truck drivers from the southern Maine dealer, according to the affidavit. The report stated that the informant reported that there was at least $5,000 in the envelopes.

The informant also reported seeing several yellow manila envelopes of cash in a safe at Thompson’s home that looked like the ones turned over to Thompson by drivers from the southern Maine dealer.

In February, the cooperative board members hired a company to install surveillance and recording equipment at the Spruce Head Island facility while Thompson was on vacation.

A review of the surveillance videos showed that 17 crates of lobsters had been shipped to the southern Maine dealer that were not recorded by Thompson during the past four months. The minimum value of those lobsters was estimated at nearly $14,000.

A review of business records also found that no receipts were being collected by Thompson when the dealer’s trucks picked up lobsters. Receipts were received from other buyers.

The cooperative board members told officers that they believed Thompson was creating extra crates of lobsters by manipulating the scales that weigh incoming lobsters.

Later surveillance in September showed no discrepancies but board members said Thompson had been on edge and they believe he knew he was under suspicion.

The board members recounted examples of expenses incurred by Thompson for his home and a residence in Rockwood that made them suspicious he was living beyond his means. The board members said that renovations to the Rockwood residence exceeded $100,000, and that he made made additions to his home in St. George including a new garage.

The unnamed informant reported to police that Thompson had put nearly $100,000 into restoration of a 1968 Chevrolet Camaro and that he had purchased seven snowmobiles for various family members.

Four search warrants were executed by police during the first week of October, one at Thompson’s home in St. George, one at his residence in Rockwood (both of which are co-owned by his wife), one for Thompson’s safety deposit box at the Key Bank in Rockland, and one at the southern Maine dealer.

The National Marine Fisheries Service, the Internal Revenue Service, the U.S. Coast Guard and the Maine Marine Patrol also have assisted in the investigation, according to the sheriff’s office.

A telephone call was made to the southern Maine dealer. The owner was not available for comment because he was on vacation, according to a man who answered the phone at the business. The man, who would not give his name, said there would be no comments on the allegations, which he said were just speculation.

Thompson’s attorney Walter McKee of Augusta said Friday morning he had yet to see the affidavit but was pleased it was finally released. He had filed a motion last month to have the affidavit unsealed.

“No one should have to have their home searched for secret reasons,” McKee said Friday.