A new Human Rights Watch (HRW) report concludes that at least 18 people died while in the custody of federal immigration officials over a three year period ending just last year largely due to subpar medical care in several instances.

The blistering report finds among the victims were legal immigrants, undocumented immigrants and people seeking protection under U.S. refugee laws.

In all, the report delves into the details surrounding the deaths of 31 who died while in the custody of Immigration and Customs Enforcement (ICE) Office of Detention Oversight (ODO).

Experts Find Several Deaths Preventable

As part of the analysis, HRW officials employed the services of at least two independent medical experts who have since ruled at least seven of the 18 deaths in question were more than likely preventable. Researchers noted 13 of the original 31 cases tabbed for examination were not independently studied because ICE did not release sufficient information related to them.

Among the deaths medical experts deemed preventable was the case of Manuel Cota-Domingo, a 34-year-old immigrant from Guatemala who died of heart disease, untreated diabetes and pneumonia.

From the time he began complaining of chest pains, experts found Cota-Domingo was denied medical attention for eight hours due to reasons that included an Eloy Detention Center policy that forbidding certain medical staff from calling for emergency services.

"If diagnosed properly and treated, diabetic ketoacidosis and pneumonia are treatable," Dr. Allen Keller, one of the two medical experts, said. "But both of these life-threatening diagnoses were missed at the detention facility."

Another maddening instance came in the case of Raul Ernesto Morales-Ramos, a 44-year-old immigrant from El Salvador who is believed to have suffered from undiagnosed cancer.

While being held at the Theo Lacy Facility, medical experts found his gastrointestinal symptoms went unaddressed and he was never "appropriately referred for specialist care."

Advocates Push for Reforms 

By and large, HRW officials insist their findings point to the need for additional reforms to the immigration detention centers used by the government to house the thousands of immigrants facing deportation proceedings.

 Shocking as some of the findings may be, there not surprising to many of those in the know, who insist facilities like Eloy and Theo Lacy have long been among the most "notorious" as it relates to providing substandard medical care.

"More people have died at Eloy since 2003 than at any other immigration detention facility," said Christina Fialho, co-executive director at the immigrant rights group Community Initiatives for Visiting Immigrants in Confinement (CIVIC).

The ACLU and the immigrant rights group Detention Watch Network previously named Theo Lacy one of the worst detention centers in the U.S. As recently as last year, 10 detainees filed a complaint against the facility alleging physical abuse, medical neglect, and retaliatory transfers.

In all, 14 deaths have been reported at Eloy since 2004, including several suicides.

Indeed, both experts used by HRW expressed grave concerns about the quality of mental health care in three additional cases of people who committed suicide. In each case, medical officials concluded subpar care contributed to the person's demise.

In addition, a previous ACLU, Detention Watch Network and National Immigrant Justice Center report entitled "Fatal Neglect" found that suspect medical standards played a major role in another eight in-custody deaths from 2010 to 2012.

In that instance, ICE's inspection and oversight channels were considered to have failed to identify or address problems that contributed to the person's death.