Huawei began building its own phone-testing system, xDeviceRobot, in early 2012. The Chinese company hoped to improve the quality of its mobile hardware, which tended to fail far more often than competitors' devices in third-party trials. In May 2012, Huawei China asked T-Mobile if it could license or flat-out buy the company's phone-testing robot, Tappy, which served as a standard for much of the industry. So, Huawei decided to steal Tappy. After installing a handful of employees at T-Mobile's headquarters in Bellevue, Washington, federal prosecutors claim Huawei USA and China employees attempted to illegally collect information on Tappy in a year-long espionage campaign that culminated in actual theft.

A Justice Department indictment unsealed on Monday details an alleged conspiracy by the Chinese device maker Huawei to steal the details of a T-Mobile robot. Here, a woman uses her smartphone outside a Huawei store in Beijing on Tuesday. A Justice Department indictment unsealed on Monday details an alleged conspiracy by the Chinese device maker Huawei to steal the details of a T-Mobile robot. Here, a woman uses her smartphone outside a Huawei store in Beijing on Tuesday. But only one of them reads like the script of a slapstick caper movie.

The twin criminal indictments against Huawei unveiled by US authorities on Monday are packed with emails and financial transactions allegedly showing how the Chinese technology giant carried out criminal conspiracies. But the finer points of the 23 charges are less important than the overall shot they deliver across China's bows. The US considers Huawei to be an arm of the Chinese state – and their devices to be potential spying equipment for Beijing. Charges that Huawei illegally violated US sanctions on Iran hold the most symbolic significance. They allowed Kirstjen Nielsen, the homeland security secretary, to stress the company's activities had been "detrimental to the security of the United States".

One Huawei employee, identified in the indictment only as "R.Y," wrote in a January 2013 email to Huawei China that, "Once again, we CAN'T ask TMO any questions about the robot. TMO is VERY angry the questions that we asked. Sorry we can't deliver any more information to you." The employee suggested Huawei China send its own engineer to the Seattle lab.

Chinese telecom giant Huawei is at the centre of an increasingly tense standoff between China and the US. What began as a trade spat and grievances over corporate intellectual property theft has developed into a global standoff involving "hostage diplomacy", death sentences and allegations of Chinese espionage. Huawei's senior executive Meng Wanzhou, was arrested in Canada in December over allegations of sanctions violations, and awaits extradition to the US. Meanwhile, three Canadians remain in police custody in China – with one of them sentenced to death this month. Washington, meanwhile, has said it will file a formal extradition request for Meng by the 30 January deadline.