MEXICO CITY (AP) — Mexican authorities have detained a suspect in the killing of a Canadian couple during an apparent robbery at their lakeside home in a popular retirement spot in western Mexico.

Jalisco state prosecutors say they have detained Julio Castillo, a 31-year-old bricklayer who authorities say broke into the couple's home in Chapala on Sunday along with his brother.

Prosecutors said in a statement Thursday that Castillo's brother remains at large.

A gardener found Linda Marian Discombe and Edward J. Kular in a pool of blood in the living room of the house where they'd lived for at least six months.

Authorities say Castillo told investigators he had been working at a home next door and planned to rob the Canadians' home because he thought Discombe lived alone.