The family of an Ontario woman, who went missing while attending the Shambala Music Festival in B.C., tried to call her sister shortly before disappearing, her family says.

RCMP are looking for 28-year-old Kayla Boisvert of Trenton, Ont., who was attending the four-day electronic music festival held near Salmo, in B.C.’s West Kootenay region.

They say she was last seen at at the festival around 2:15 a.m. PT on July 27.

News of her disappearance was widely shared across social media in the immediate aftermath, with anyone with information urged to contact police.

Friends and family say Boisvert works as a paramedic and frequently attended festivals, and that it is highly unusual for her to not stay in contact throughout the event.

Now, her twin sister says she received two calls from Boisvert shortly after she was last seen.

“I was sleeping and called her back instantly when I realized that she called,” Dianna Boisvert said in a statement to CBC News, and said that when she tried to call her sister back, the call went straight to voicemail.

Dianna Boisvert said she spent the next day scouring social media and messaging people who knew her sister and were attending the festival, knowing her sister was camping in an area with poor connectivity.

Shambhala bills itself as Canada’s largest outdoor electronic music festival, held on farmland along the Salmo River about 400 kilometres east of Vancouver. It says more than 21,000 people were involved in this year’s sold-out event, including artists, staff and ticketholders.

In a statement, the festival says it is working closely with RCMP and public safety agencies to support the search for Boisvert.

Dianna Boisvert said she wants people to know that her sister is “an incredibly strong person, an accomplished deadlifter,” as well as a paramedic and academic who studied at McMaster University.

“We want our sister, daughter, friend home safe.”