Washington CNN  — 

A Cuban man who died Monday morning in Miami is the sixth person to pass away since October while in custody of Immigration and Customs Enforcement.

The 63-year-old’s name is being withheld pending notification of next of kin, according to the agency. He died at Miami’s Larkin Community Hospital, where he had been receiving inpatient medical treatment since Thursday.

No details were provided about the treatment he had been receiving. The preliminary cause of death was ruled to be cardiac arrest, according to ICE. The news of the man’s death was first reported by BuzzFeed.

At the time of the man’s death, he was awaiting deportation to Cuba – part of an immigration court order from 2000. Over the past few decades, he had faced various criminal charges, including a conviction on heroin charges and assault with a weapon.

He was taken into ICE custody on January 14, after he had been convicted and sentenced to 15 days in jail for theft.

The man’s death marks not only the sixth death in ICE custody since October, but also the second in ICE custody in Florida in the past week after a British man was found dead Saturday.

Ben James Owen, 39, was found unresponsive in his cell in a Florida ICE detention center, according to the agency. The cause of death “appears to be self-inflicted strangulation” and the case is currently under investigation, ICE said in a news release.

In all, eight people died in ICE custody in fiscal year 2019. Fatalities in ICE custody are “exceedingly rare” and occur at a rate roughly 100 times lower than the average for federal or state facilities nationwide, according to ICE spokesperson Bryan Cox.

Still, the recent deaths have drawn sharp criticism from immigrant rights activists, who have long decried conditions in immigration detention centers and called on the government to close such facilities.

A report from the Department of Homeland Security inspector general released last year found expired food and dilapidated bathrooms during unannounced visits to four immigrant detention facilities in 2018.

The inspector general had observed unsanitary conditions in the bathrooms at the Adelanto and Essex facilities during the surprise visit. “(W)e observed detainee bathrooms that were in poor condition, including mold and peeling paint on walls, floors, and showers, and unusable toilets,” the report reads.

Other issues raised include spoiled food; lack of provisions, like lotion, that are required for detainees; and strip searches with no documented justification. The report notes that ICE detainees “are held in civil, not criminal, custody, which is not supposed to be punitive.”

In a response included in the report, ICE said it has resolved, or worked to resolve, the issues flagged by the inspector general.

CNN’s Priscilla Alvarez contributed to this report.