Prosecutors said Friday they are weighing felony charges against a Sun Country Airlines employee who is accused of stealing a conference championship ring won by a former Minnesota Gopher when he played in the NFL.

The ring, which police eventually tracked down, was earned by Mark Slater when he was a center for the Philadelphia Eagles when they won the 1980 National Football Conference title before losing to the Oakland Raiders in the Super Bowl.

Slater, 70, lost the ring on March 3 while on a flight from Minneapolis-St. Paul International Airport to Mesa, Ariz., according to a document filed last week by airport police in Hennepin County District Court.

The filing, a search warrant affidavit, cleared the way for police to seize the cellphone of a 39-year-old employee and look for evidence pointing to him as the thief.

Police have turned over the case for consideration of charges, according to a spokesman for the Hennepin County Attorney's Office. The filing identified the employee, but the Minnesota Star Tribune generally does not identify suspects before they are charged.

The suspect works in the terminal for Sun Country, according to the filing. A spokeswoman for the Twin Cities-based airline declined to comment on the allegations or say whether the employee still worked for Sun Country.

The rings presented to the Eagles players, coaches and other staff were made with 10-karat gold and produced by Twin Cities-based Jostens. Each ring displays an eagle clutching a football sporting a half-carat diamond atop a green stone. The left side displays the recipient's surname.

Auction websites show the rings have been put up for bid for thousands of dollars over the years, with the price depending on the prominence of the recipient and the ring's condition.

According to the filing:

Slater, who lives in his native North Dakota and played for the Gophers in the 1970s, reported to police on March 11 that he dropped the ring during the flight.

A passenger on the same aircraft returning to the Twin Cities from Mesa found the ring, determined it belonged to Slater and got word to him. The passenger said he turned it in at a Terminal 2 gate at MSP.

Surveillance video at the gate from 12:30 a.m. on March 4 showed the ring being given to the employee now under investigation.

The employee left the gate holding the boxed ring and did not enter Sun Country's baggage office, where lost items are stored.

Police on March 11 inspected the airline's lost and found records and saw the ring was not logged in. A detective and a Sun Country staffer searched the baggage office in vain for the ring.

A Sun Country manager called the suspect and ordered him in to work early. During the call, the employee said he hid the ring in the manager's office and would be able to find it.

Police deactivated the employee's security badge, preventing him from potentially entering the office and planting the ring.

The employee went to the office and could not get in. He then called the manager and soon entered.

Officers saw on surveillance video that the employee "had a bulge in his left pants pocket that was consistent with the size and shape of the ring box when he walked into the [office]," the filing read. "Officers observed that the bulge was gone when [he] left.

"It appeared that [the employee] had the ring on his person and hid it in the [office] prior to speaking with officers," the filing continued.

Officers approached the employee near a baggage carousel. They went to the office, where he showed the officers that the ring was in a drawer for a first aid kit and supplies, "not ... a normal storage area for lost and found items," the filing noted.