ONLINE retail giant Amazon could face a legal battle with a Spanish workers’ union following a report that it hired private investigators to infiltrate and secretly observe a strike. 

Spanish news site El Diario revealed this week that private detectives spied on a warehouse workers’ strike near Barcelona on Black Friday last year.

The strike was part of a broader action in Catalonia and around the world to protest against insufficient pay and poor working conditions.

According to a 51-page document obtained by El Diario, the private detectives were employed by Spanish company Castor and Polux.

A separate report by Motherboard has also revealed that Amazon employed the detective agency to monitor union activity across Europe. 

The recent document contained photographs of trade unionists, workers and journalists who attended the strike, according to the report. 

It reads: “We saw a group of people meeting, who could be seen wearing The Workers’ Commissions (CCOO) and The Union General de Trabajadores (UGT) union bibs/vests. 

“They’re recorded for possible identification at subsequent events.”

Trade union CCOO said in a statement: “CCOO wants to know if Amazon carried out, through a contracted company, exhaustive monitoring of people, photographs, and prepared reports of workers and trade unionists. 

“The union will assess with its legal services the filing of a criminal lawsuit against Amazon.”

CCOO also warned that if the claims are true, it would mean Amazon broke Spain’s constitutional laws on the right to assembly and data privacy.

UNI Global Union general secretary Christy Hoffman told Business Insider that Amazon was “using its immense power and resources to snoop on workers looking to improve their jobs.”

“As bad as spying on workers is, it doesn’t come in a vacuum,” she added. 

“There’s a pattern here. Amazon’s enormous appetite for growth is bad for our societies. 

“This is why, on Black Friday, more and more people who believe in the dignity of work and the politics of the common good went on strike to stand up to Amazon, demanding change.”

Castor and Polux declined to comment when contacted by El Diario, citing client confidentiality. 

An Amazon spokesperson told El Diario thta the firm had not instructed any agencies to spy on the strike.