Critics of the Canada Border Services Agency are calling for more independent oversight after a person detained by the agency died Monday morning at the Toronto East Detention Centre.

Samer Muscati, director of the University of Toronto law faculty's international human rights program, said at least 13 people have died in the custody of the CBSA and its predecessor since the year 2000. He called it a "shameful" fact.

"This latest death is a further stain on CBSA's reputation and highlights the urgent need for reform of the way immigration detention is practiced in this country," he said.

Travis O'Brien, communication advisor for the agency in the Greater Toronto Area Region, said he could not confirm the sex or age of the person and could not say whether the person was a permanent resident or foreign national.

"We are reviewing the circumstances around the death," he said Tuesday.

O'Brien said the person was in the care and control of the Ontario Ministry of Community Safety and Correctional Services. According to the agency, the person was "under CBSA immigration detention."

Mitch Goldberg, president of the Canadian Association of Refugee Lawyers, said in Montreal the death raises questions.

'The public needs answers'

"Nobody should die while they are in the custody of CBSA. The public needs answers. What was the cause of death? Could this death have been prevented?"

Laura Track, a staff lawyer with the BC Civil Liberties Association in Vancouver, said it's clear from deaths in custody that the agency needs independent oversight and accountability.

"Parliament has given CBSA broad powers of arrest and detention, yet it remains alone among major Canadian law enforcement agencies in having no independent oversight," she said.

"When deaths happen in custody, we need independent, civilian-led investigations if the public is to have any confidence in the results. This reform is long overdue."

Track said a coroner's inquest jury into the 2013 death of a Mexican woman in CBSA custody, Lucia Vega Jimenez, recommended independent oversight for the agency.

Jimenez, who was facing deportation, was found hanging in a CBSA shower stall in Vancouver. She died in hospital days after being removed from the CBSA holding cell at Vancouver's airport.

"It's unfortunate that these deaths in custody continue to happen," Track said.

CBSA says it's co-operating fully

A person can be detained if a CBSA officer believes the person:

Is inadmissible under the Immigration and Refugee Protection Act.

Poses a danger to the public.

Is unlikely to appear for an examination, an admissibility hearing, or a removal from Canada.

Cannot prove his or her identity to the officer's satisfaction.

Immigration law allows for the arrest and detention of foreign nationals without a warrant.

In the Greater Toronto Area, the agency relies on provincial correctional facilities to hold higher-risk detainees.

O'Brien said an investigation into the death has begun and the agency is co-operating fully.

"As is the case with any death in custody, the CBSA takes this matter seriously and will complete a review of the circumstances surrounding death to identify any factors that could be addressed to prevent any future loss of life," the agency said in a news release.