Miami-Dade’s jail system engages in a “pattern and practice of constitutional violation” against inmates that includes woeful medical and mental illness care that sometimes leads to death, abuse by corrections officers, repulsive living conditions and the failure to properly supervise dangerous offenders, according to a sweeping federal investigation.

The report, released Friday, concluded a three-year review by the U.S. Dept. of Justice into the troubled corrections department, one of the largest in the nation. Among the findings:

• The corrections department is “deliberately indifferent” to the suicide risks and mental health needs of inmates. The study noted that at least eight inmates have committed suicide since 2007, and staffers are not trained to deal with suicidal patients.

• The jail does not provide proper medical care, failing to provide proper screenings and health assessments — even botching the dosages of medicine handed out on a daily basis. Since 2008, at least five inmates have died after jailers failed to treat them as they withdrew from drugs or alcohol. Also, “the jail does not track prisoners with chronic illness nor monitor their conditions,” the study said, noting patients with HIV, diabetes and hypertension and histories of seizures go unmonitored or untreated.

•  Jailers engaged in excessive force against inmates, retaliating against them, frequently causing injuries and failing to properly document their interactions. In one case in August 2007, up to nine officers stood around and allowed a jailer to fight an inmate in a “prolonged fistfight.”

• The conditions at the aging and unsanitary jails pose serious health risks to inmates, particularly at the 50-year-old main jail in central Miami. The fire systems appear woefully inadequate, officers are undertrained in safety measures, and sanitary conditions are unacceptable.

“Bags of biohazardous materials and trash were stored in hallways unsecured and unattended,” the study recalled of one visit to the MetroWest Detention Center’s medical clinic. “The isolation cells in the clinic were filthy. One cell contained a bloody sheet that had not been removed from the bed.”

If improvements are not made, the U.S. Attorney General’s Office could sue and the corrections system could yet again be placed under the supervision of a federal judge, as it was in the 1980s.

The release of the scathing report drew swift reaction from politicians.

“I am deeply concerned about the Department of Justice’s findings, and will be reviewing the progress that has already been made to address them,” said Miami-Dade Mayor Carlos Gimenez. “The Department of Justice has my personal assurance that they will get total cooperation from Miami-Dade County in this matter.”

Corrections Director Tim Ryan, hired in 2006 to help overhaul the notorious jail system, declined to comment.

Officials of Jackson Health System, which administers health care for the jail system, issued a statement saying administrators are “working closely” with federal investigators.

“Many changes have already been implemented since the DOJ site visits in 2008 and 2009, and our proposed budget for the coming year would address many others,” the statement read. “We are committed to finding quick, effective and long-lasting solutions that will ensure that all inmates are provided with quality and timely health care.”