(CNN) -- A suspicious piece of luggage that was about to be loaded onto a flight in Namibia was a "test device" from a U.S. company that sells products designed to test security, German Interior Minister Thomas de Maiziere said in a news conference Friday in Hamburg, Germany.
Namibian police on Friday warned that whoever is responsible for planting the device among the luggage of an Air Berlin flight Wednesday would be severely dealt with, warning that Namibia was not to be used as an unauthorized testing ground for aviation security.
"The preliminary investigations have revealed that the suspicious parcel does not contain any explosive substances; however, it is an explosive simulation training device, manufactured by an American-based company, 'Larry Copello Incorporated,' " Lt. Gen. Sebastian Ndeitunga, Namibia's top policeman, told reporters Friday at a news conference in Windhoek, the capital.
The device is a training aid to help screeners identify explosive devices, Larry Copello, founder and CEO of Larry Copello, Inc., told CNN Friday. Copello described the device as "non-hazardous ...not a threat to anyone."
Copello said his company sells such devices to law enforcement agencies, governments and corporate clients, but did not know to whom this particular device was sold. He learned of the Namibia incident on Thursday when the FBI called him. He said he is cooperating with the investigation.
An official with the U.S. Transportation Security Administration said Friday that they are working with German and Namibian authorities to determine the origin of the device and the reason it was to be transported on the plane.
"We applaud the vigilance of the aviation security authorities who discovered the device and took quick action to ensure that it did not pose a threat to the aircraft and passengers," the TSA official told CNN.
A U.S. official said Friday that there doesn't seem to be any connection with any U.S. government entity.
The discovery of the bag at Windhoek Hosea Kutako International Airport in Namibia delayed flight 7377 to Munich, Germany, on Wednesday and raised security concerns, a spokeswoman for the airline, Air Berlin, said Thursday.
De Maiziere said he believed the device was from a U.S.-based company, but did not know which company. He said no one was warned in advance about the test device. The bag contained a functioning electronic clock with wiring attached, but no explosives.
"Air Berlin has confirmed that there was no explosive material in the laptop bag found in Namibia," Sabina Teller, a spokeswoman for Air Berlin, told CNN. "The luggage was found in the airport, at no point was on the plane. It had no luggage label, so it was impossible to know where it was going, which company it was supposed to fly with or who it belonged to," she said
De Maiziere said authorities are investigating the bag's origin and its intended destination.
After the bag was discovered, the flight's 296 passengers and all bags were given additional security checks. The plane later landed safely in Munich after a six- or seven-hour delay, Air Berlin spokeswoman Silke Manitz said.
Germany raised its threat level Wednesday, saying concrete evidence had emerged of a possible attack planned in Germany later this month. It said there was evidence of persistent efforts by Islamists to launch an attack. A senior German counterterrorism source told CNN on Thursday that the German Interior Ministry warning was linked to recent threats to the country from al Qaeda in Pakistan.
Interior Minister de Maiziere addressed the threat level Friday by reiterating that people should go about their lives as usual.
CNN's Laura Perez Maestro in London; Ben Brumfield in Atlanta, Georgia; Diana Magnay in Hamburg, Germany; John Grobler in Namibia; Nkepile Mabuse in Johannesburg, South Africa; and Jeanne Meserve in Washington contributed to this report.