Global Affairs Canada says consular officials "urgently" want more information about a Canadian's death while in ICE custody in Miami.
Johnny Noviello was awaiting deportation proceedings when he was pronounced dead at a U-S federal detention centre on Monday.
Foreign Affairs Minister Anita Anand says the U-S notified Ottawa about the death, yesterday.
U-S Immigration and Customs Enforcement says it arrested Noviello in May at a Florida probation office.
Noviello had been sentenced to a year in jail in a conviction for racketeering and trafficking opioids.
The 49-year-old had been in the U-S since January 1988 and became a legal permanent resident in October 1991.