The Hawai'i Supreme Court has overturned the prostitution conviction of a woman who "dirty-danced" with an undercover police officer in a hostess bar after he bought her two $40 drinks.

The court ruled that prosecutors failed to prove that the defendant, Jing Hua Xiao, "had an implicit understanding" that the drink purchases also were meant to buy sexual services.

The defense argued successfully that sexual contact which occurred when the pair was "dirty dancing" while fully clothed inside Club Sara Lee in 2006 was "merely gratuitous " and not criminal in nature.

The undercover officer, Joel Wagner, testified that he had been to the club several times before and that Xiao only offered to dance with him when he bought her $40 drinks instead of $20 drinks.

When they danced, Wagner testified, Xiao rubbed her pelvis into his groin and caused him to become sexually stimulated.

"She then said, 'Oh, what's this?' and then began to grind harder," Wagner testified.

That conduct, combined with the $40 drink purchases, constituted prostitution, Wagner testified.

When questioned by defense attorney William Harrison, Wagner said Xiao never told him she would "do anything to you for that $40 drink."

District Judge Edwin Nacino, who has since been elevated to the Circuit Court bench, convicted Xiao of the prostitution charge in December 2006, fined her $500 and sentenced her to six months of probation. The sentence was stayed while the case was appealed.

The Intermediate Court of Appeals upheld the conviction last November but the high court overturned it yesterday in a 4-0 decision written by Chief Justice Ronald Moon.

Justice Simeon Acoba wrote a separate opinion that agreed with the outcome of the majority decision but dissented with its reasoning.