Phu Tho provincial police have opened a criminal case against Nguyen Minh Hieu, 23, over allegations he raped the 24-year-old woman on July 5.
Police say the assault took place in an apartment at the Lynn Times Thanh Thuy hot spring resort in Thanh Thuy Commune, in the northern province.
Investigators named Hieu, a resident of Hanoi's Tu Liem Ward, as the accused on Aug. 17 after the provincial People's Procuracy ratified the decision, and announced the case two days later.
Rape under Clause 1, Article 141 of the Penal Code carries two to seven years in prison.
The woman filed a complaint on July 21, more than two weeks after the alleged assault.