A dummy bomb that sparked an international terror alert was made by an 80-year-old woman in California and ended up discarded in a Namibia airport because of "a boo-boo," NBC News reported Friday.
The device — part of a "modular bomb set" or MBS, which is used for X-ray and physical/bag search training — was manufactured by a "mom and pop" machine shop in Sonora called Larry Copello Inc. four to five years ago.
The owner, Larry Copello, told NBC News that his then-80-year-old grandmother had completed it, doing the wiring and fitting Velcro attachments.
The device was found at Windhoek airport by Namibian police in routine security checks during loading ahead of an Air Berlin tourist flight to Munich, Namibian and German authorities said Thursday.
Germany has been in a heightened state of alert this week with warning of a possible terrorist attack.
Coppello told NBC News that he had no doubt that "someone made a boo-boo."
The device was not functional, completely inert and unable to make a spark, he added.
Copello confirmed he was visited by U.S. law enforcement Wednesday, soon after the device was discovered.
It remains unclear what agency or who left the bag containing the device at the airport and whether it was part of a test, an accident or a malicious act.
The device contained batteries wired to a clock and a detonator.
Germany sent federal crime experts to Namibia to examine the device. German Interior Minister Thomas de Maiziere said Friday that the alarm was simply a test of local security and confirmed the device had not contained any explosives.
"Officials have examined it and the result is that it is a so-called 'real test suitcase' from a U.S. company," he said.
"This company produces alarm and detection systems and these test suitcases are made to test security measures," De Maiziere added, without naming Copello.
Angry calls from White HouseDe Maiziere said police trying to find out if German security services were behind the incident, .
"I consider that highly unlikely, but that is one of the things we are looking into," he said, according to the Times. "The important thing for all of us is that no explosives were found in the luggage and that, as far as we know at this point in the investigation, there was at no point a danger to passengers posed by this luggage."
Washington had been putting pressure on Germany to take the threat of possible terrorist attacks more seriously, the Times said, adding that Berlin officials reported receiving angry calls from a White House official.
The U.S. official had demanded heightened vigilance, the Times reported, and the message had been passed on the German Chancellor Angela Merkel. However, despite this, Germany had continued to see the risk as an "abstract" one, according to the report.
In Namibia, police Inspector-General Sebastian Haitota Ndeitunga confirmed it was made by Larry Copello Inc. and reacted angrily to the news the bomb was a test device, .
"The Namibian Police Force want to send out a stern warning to people with ill intentions that it will not allow Namibia to be used as a testing ground by anyone," he told reporters, according to the news service.
Ndeitunga added that they would "severely deal with" the person who had left the device at the airport.