Warning: Some may find details in this story disturbing.

In a tour of the site of a former residential school in B.C. that is now being used as a daycare and office space for his nation, a survivor found a jail cell with a small bed and toilet.

Chief Ralph Leon Jr. of the Sts’ailes First Nation told APTN reporters he was forcibly taken from his community to the St. Mary's Indian Residential School when he was 10 years old.

On the tour, APTN reporters and Leon discovered the jail cell, which looks out onto a children’s playground. He said he didn’t previously known it was there.

"I knew about certain places," Leon said. "But we weren't allowed there and we didn't know."

APTN was not able to confirm if this jail cell was from the residential school era, but other survivors from across Canada have testified that they recall jail cells in other residential schools.

St. Mary's was first founded as a boarding school in 1863, but then re-opened as a residential school in 1882. It was officially closed in 1984.

On the tour of the site, Leon said certain parts of the school hold particularly terrible memories.

"This little room you didn't want to end up in," Leon said of one of the spaces at the former residential school. "The things I witnessed in this room is devastating to any human being. All abuses happened in this room."

Until this tour with APTN, Leon had not returned to St. Mary's since his days there.

"I haven't come back here because of what is still in my mind, what I witnessed here: mental abuse, physical abuse, sexual abuse, verbal abuse," Leon said. "So no amount of money, no counsellor could ever take that away from my mind."

Investigations into St. Mary's resulted in a former school employee being convicted in 2004 of 12 counts of indecent assault and sentenced to three years in prison.

Leon and a few of his family members participated in the Indigenous delegation that travelled from Canada to Rome last month to meet with Pope Francis at the Vatican.

On April 1, the Pope offered an official apology on behalf of the Catholic Church for its role in the abuses carried out in residential schools, and reiterated plans to visit Canada.

Leon said the apology helped him and his wife on their healing journey.

"The spirit of our ancestors are with us, and that's why it's emotional," Leon said.

If you are a former residential school survivor in distress, or have been affected by the residential school system and need help, you can contact the 24-hour Indian Residential Schools Crisis Line: 1-866-925-4419

Additional mental-health support and resources for Indigenous people are available here.