Canada has confirmed a Canadian citizen is in police custody in Belize.
Global Affairs Canada officials did not say whether that arrest was related to the deaths of a Canadian woman and her American boyfriend.
The bodies of Francesca Matus, 52, and former marine Drew DeVoursney, 36, were recovered on Monday.
They had been missing since 25 April.
Austin Jean, a spokesman for Global Affairs Canada, said on Thursday that consular officials are assisting the family of the detained Canadian and in contact with local authorities to gather additional information.
Mr Jean said Canada will not release more information to protect the privacy of the individual.
Police in Corozal, where the couple were last seen, told the BBC that a person who had been detained has since been transferred to another jurisdiction in Belize, but said they were not at liberty to discuss further details in the case.
Police in Placencia, a beach resort town south of Corozal, confirmed they were holding a Canadian in custody.
Matus’s and DeVoursney’s bodies were found in a sugar cane field on Monday night.
The family says that both appeared to have been strangled and their hands were tied with duct tape.
The couple were last seen leaving a bar in the town of Corozal, on the northern coast of Belize near the Mexican border.
They had been dating for a few months.
DeVoursney, an ex-Marine, was described by family as “adventurous and committed”.
After doing tours of Afghanistan and Iraq, he worked as private contractor in both regions, teaching marines how to use computer equipment in the field.
Matus was reportedly the mother of two adult sons. She spent her winters in Belize.
Canadian citizen in custody in Belize