The former head of the country's largest jeweller was arrested earlier this month along with more than 30 others accused of involvement in a syndicate operating over several years.

Analysts say PNJ faces ‘significant’ reputational risk from the case involving the former director of its gem certification subsidiary.

HANOI, July 15 — Vietnamese police are investigating an international diamond ring accused of smuggling 28,000 gems worth nearly US$11 million, with the country’s largest...