ATLANTA -- The 25-year-old man who died while participating in a sleep study at Emory Healthcare suffered "sudden cardiac death," according to hospital officials.

Brandon Harris died Jan. 23 after entering the sleep clinic the night before, according to family members. They want Emory to close the sleep clinic while Harris's death is investigated.

Harris was overweight, diabetic and suffered from high blood pressure.

An uncle said Emory officials showed him a video on which Harris can be seen signaling for help from Emory employees.

Emory refused to release that video.

"Emory cannot release the video recording of the sleep study because it must be viewed on special software that can only be seen in the sleep lab, where there are ongoing studies," according to a statement released Monday morning.

Harris's family claims the Emory staff neglected Harris when he needed help. Emory officials disagreed Monday.

"At all times during the sleep study, Mr. Harris was monitored and the providers appropriately attended to him," according to the Emory statement.

"According to the post-mortem examination, Mr. Harris died because of "sudden cardiac death," meaning that his heart stopped suddenly and without warning," the statement continued.