Four people suspected of trying to smuggle heroin from Mexico have been arrested at Calgary International Airport. 

The Canada Border Services Agency (CBSA) seized over 900 grams of suspected black tar heroin from the four suspects as they arrived on Nov. 9, officials said.

Suspecting the travellers were hiding drugs, border guards searched them thoroughly and found they had concealed narcotics internally and on their bodies, officials said.

"Concealing narcotics internally is an extremely dangerous practice for the courier, regardless of how well the narcotics are wrapped," said Lauren Delgaty, regional director general for the CBSA in the Prairie region.

A fifth man suspected to have had a role in the smuggling was also arrested.

RCMP officers charged the three men and two women under the Controlled Drugs and Substances Act.

They will appear in provincial court in Calgary between Nov.15 and Nov. 22.