But the T.S.A. said on Thursday that officials had examined the bag tag that was affixed to the case and crosschecked it with its checked baggage screening records. They then learned that the instrument case had been screened through a scanner but had not triggered an alarm, the T.S.A. said.

That “means that T.S.A. did not open the case,” according to the T.S.A.

A decal was placed on the case to show it had been screened and cleared, the T.S.A. said. The case was then moved to a conveyor belt and sent to the airline baggage room so it could be loaded on the plane, according to the T.S.A.

On its website, the T.S.A. explains that it screens 1.4 million checked bags daily for explosives and other dangerous items. Most bags are not physically searched by an agent, but if a bag is opened, the T.S.A. will place a notification inside saying that the bag was opened and checked. Once the screening process is finished, the airline brings the checked bags on to the flight.

Mr. Sissoko had been performing with his band 3MA, a trio of musicians that also includes Driss El Maloumi, an oud player from Morocco, and Rajery, a valiha player from Madagascar, according to the statement released by Ms. Serres and Mr. Sissoko’s website.

Following the process Mr. Sissoko normally takes when flying, the musician and his tour manager on Sunday night dropped off the kora at the oversized luggage desk at Kennedy Airport, where the case was scanned, Ms. Serres said by email.

Nobody at the counter expressed any concerns, she said.

On its site, the T.S.A. states that “musical instruments must undergo screening when transported as carry-on or in checked bags.” If an instrument requires any special instructions or handling, passengers should tell a T.S.A. agent, the agency says.