China’s railway police have arrested 18 suspects allegedly involved in international women trafficking, rescuing 12 Vietnamese women.

The suspects belong to two human trafficking groups, according to a statement of the railway police on May 25.

Railway police launched the investigation after a suspect surnamed Li was found trafficking a Vietnamese woman on a train running from Kunming, capital city of southwest China’s Yunnan Province to Jinan, capital city of east China’s Shandong Province on December 12.

In the following five months, a special team seized another 17 suspects in Yunnan and Hunan provinces and rescued the other 11 Vietnamese women in central China’s Hunan Province.