TAIPEI (Taiwan News) – Police in Keelung City detained eight members of the Navy gambling at a mahjong parlor Tuesday (Sept. 3), Armed Forces Day.

Acting on a tipoff, police and prosecutors spent more than a month lying in wait near a location advertising itself as a leisure club for card players. The site was raided last year for illegal gambling, but the owner did not mend his ways, the Liberty Times reported.

Of the eight Navy members detained, one held the rank of commander. The club had introduced a membership system, but the threshold was low, with new arrivals immediately receiving a membership card at the entrance.

Noticing a high number of people entering the club Tuesday, police and prosecutors decided to act. Investigators joined the gamblers undercover before revealing their identities and making arrests.

Police detained 52 suspects and found NT$110,000 (US$3,400) in cash, as well as other evidence. The owner turned out to be a retired police officer, who was freed on bail of NT$200,000.