Five residents of a Manhattan nursing home have died after an outbreak of Legionnaires’ disease was detected at the facility, and at least four of those deaths are directly linked to the disease, according to the state Department of Health.

Officials last week announced that four residents at the Amsterdam Nursing Home in Morningside Heights had died, but noted at the time that only two were confirmed to have had the disease, and that no cause of death had been determined in any of those cases.

The number of deaths at the nursing home was updated to five on Friday, Legionnaires’ disease was determined to be the cause of four of those deaths, according to the state DOH. The cause of the fifth death currently remains under investigation.

The DOH said Friday that eight residents of the nursing home were confirmed to test positive for the disease. They previously said the eight cases were detected between June and early September of this year.

According to the DOH, Legionella, the bacteria known to cause Legionnaires’ disease, is a bacteria that is found naturally in the environment and grows best in warm water.

The source of the Legionella has yet to be found, according to Amsterdam Nursing Home spokesperson Jeff Jacomowitz.

“Amsterdam Nursing Home continues to work closely with the New York State Department of Health to find the source of the bacteria.  Every passing is a tragedy and these residents were also part of our family.  Our hearts go out to the families and all of their loved ones,” Jacomowitz said in a statement.