The spotlight on suspected serial killer Sararat “Am” Rangsiwuthaporn has now expanded to her ex-husband, a police officer, after investigators said she could not have committed the alleged murders without help.

Three Vietnamese men, with alleged links to a passport-forging gang that caters to those wishing to travel to the United Kingdom, and their Thai male accomplice were arrested in Bangkok at the weekend, Immigration Bureau chief Pol Lt-General Surachet Hakpal told a press conference on Tuesday.