BALTIMORE - Freddie Gray was listless, lethargic, and asking for assistance, but instead of summoning an ambulance, Officer William Porter propped him up so Gray could continue his ride in the back of a police van, the officer said in a recorded interview shown to jurors Friday.

Gray was handcuffed and shackled but unrestrained by a seatbelt during the ride, and at some point, he broke his neck and died a week later. Prosecutors and attorneys for the officer disagree on when and exactly how Gray was critically injured. Porter faces manslaughter and other charges in the death of Gray.

The nearly hour-long video is central to the state's case and could play into the trials of five other officers charged in Gray's death April 19. Prosecutors say Porter ignored his training and department policies requiring officers to call a medic for prisoners who ask for one.

"I said, 'Do you want a medic?' He said, 'Yes,' " Porter told the detectives.

Porter said that at one stop, Gray, lying on the floor of the van, asked for help.

"I said, 'What's up, dude?' He says, 'Help me, get me up,' " so Porter propped him into a sitting position on a bench, the officer told investigators. He said he didn't buckle Gray in because "these wagons are very small," making it difficult to get in and "ask him nicely to sit up so you can buckle him."

Porter said he told the wagon driver, Officer Caeser Goodson, "take this dude to the hospital." Porter said he then drove off in his squad car to respond to an unrelated call.

Goodson, who is also charged in the case, instead picked up another prisoner before driving the van to the Western District police station.

Porter said he didn't call a medic himself because he assumed Gray was simply exhausted from deliberately kicking and banging the walls of the van. "You couldn't tell he was hurt in any way, shape or form," Porter said.

At the last stop, a police station, Porter said he opened the back door and saw the handcuffed and shackled prisoner unresponsive on the floor of the van. Porter said an ambulance was called after he pulled Gray from the van and tried with another officer, Zachary Novak, to revive him with a "sternum rub," a technique intended to elicit a pain response.

Porter said that when that didn't work, Novak uttered an expletive and said, "We need to call for a medic."

The video was shown during the testimony of Detective Syreeta Teel, who investigated Gray's injuries for the department's Force Investigation Team.

Under cross-examination, Teel testified that Porter told her another officer called an ambulance within 10 seconds of Porter's realization that Gray was injured.

When Porter's defense attorney asked, "As soon as Officer Porter became aware of medical distress a medic was called within 10 seconds, is that correct?"

Teel said yes.