A manhunt is underway after an American woman and her Australian boyfriend were murdered while on a road trip through Northern British Columbia. Canadian police aren't saying how Lucas Fowler and Chynna Deese died, but they are investigating these deaths as homicides. Police in Fowler's native Australia said it appears they were both shot.

"At this point we have nothing to indicate that their deaths are linked to any other active and ongoing investigations," said Janelle Shoihet of the Royal Canadian Mounted Police. "It's not yet clear whether Lucas and Chynna were targeted, or if this was an opportunity, a crime of opportunity."

Stetson Deese describes his 24-year-old sister Chynna as a free spirit who traveled the world, oftentimes with her boyfriend.

"She was really adventurous, really outgoing," Stetson said. "They were both extremely nice, both very optimistic and also spontaneous."

The couple's bodies were found last Monday by their van on a highway near the Liard Hot Springs, a popular tourist destination.

Correction: An earlier version of this article incorrectly stated Fowler and Deese were killed near Canada's "highway of tears," a stretch of Highway 16 that runs between Prince George and Prince Rupert.