Mexican police have arrested five suspects in relation to the death of a University of British Columbia graduate student who was brutally murdered in Mexico last year along with her boyfriend.

Thirty-nine-year-old Canadian Ximena Osegueda and her Mexican boyfriend Alejandro Honoria Santamaria, 38, disappeared on Dec. 14.

Their remains were found a few weeks later half-buried on a beach in Huatulco, Oaxaca where Osegueda had been working on her PhD thesis.

On Monday, Mexican authorities announced the arrest of three women and two men, accused of robbery, murder and participating in organized crime, CTV British Columbia reports.

Three accomplices are still at large.

Jacy Wright, Osegueda's ex-husband who found their bodies as part of the search team, said he welcomed the development in the investigation.

"I miss her, and this doesn't bring her back. But nobody comes back, so I'm not expecting that. So this is a step in the right direction," Wright said.

When Wright discovered the remains in December they were badly decomposed and it took days for forensic investigators to positively identify the bodies.

They had both been stabbed in the neck and their remains had been burned, according to Manuel de Jesus Lopez, an attorney general in Oaxaca state.

Wright said he doesn't believe Osegueda and her boyfriend were involved in criminal activity. Instead, it's likely they were targeted for robbery because she had recently purchased a new car, he said.

"I thought that maybe would have made her a target. Several people in the community mentioned that, 'oh, she shouldn't have bought that new car,'" he said.

It was the car that led police to their new suspects. They found a receipt in the vehicle from a butcher shop, and when investigators went to the store they obtained security footage, which led to the arrest of the suspects.

A biography on the UBC website said Osegueda taught undergraduate courses at Universidad del Mar in Mexico and was specializing in colonial Latin American literature, with a focus on Mexico, in her own studies.

She received an undergraduate degree in political science, and a graduate degree in Hispanic studies, from McGill University.

"Her interest lies in the interaction between text and society: how they affect each other and how power relations are manifested in them and because of them," said the website.

At the Vancouver gym where Osegueda practiced martial arts for over a decade her photo hangs on a wall, and she is remembered as a gentle spirit who could always light up a room.

"We miss her. It always feels like she's going to come back one day," said Stephanie Pineyro.

With a report from CTV British Columbia