A federal labor official has concluded that the union victory by labor organizers at an Amazon.com facility in New York should be upheld, after the company contested the April results in which workers voted to establish a union at the tech giant.

Lisa Dunn, a hearing officer with the National Labor Relations Board, said Amazon hadn’t adequately proved that the results were inappropriately influenced, a spokeswoman with the NLRB said Thursday. Amazon had contested, saying that the NLRB region where the election was held, as well union organizers, had inappropriately swayed the vote.