The RCMP logo is seen outside Royal Canadian Mounted Police "E" Division Headquarters, in Surrey, B.C., on Friday April 13, 2018. THE CANADIAN PRESS/Darryl Dyck

Human trafficking-related charges have been laid against four British Columbia residents following arrests in Saskatchewan.

The four adults were taken into custody after an off-duty RCMP officer reported three vehicles, apparently in convoy, racing at more than 150 km/h on the Trans-Canada Highway toward Swift Current.

Mounties pulled over the vehicles and while questioning a 36-year-old woman and 23-year-old man from Victoria and 19-year-old twins from Nanaimo, officers discovered two young women travelling with them.

Neither teen carried identification and Swift Current RCMP say there were indications of human trafficking.

The four Vancouver Island residents have each been charged with five offences, including procuring a person to offer or provide sexual services, while the woman is also charged with possession of a weapon for a dangerous purpose.

RCMP say the investigation continues while the suspects make their first appearances in provincial court in Swift Current.