A witness told WFTV he went to help the officer after finding the officer on the ground.
"When I went up to him, he wasn't breathing," the man said. "He was down, nobody was helping him, so I ran to him to see what I could do to help."
He followed the instructions of a nurse, who also came to the deputy's aid.
"I was holding his hand and trying to keep him alive, keep him awake – tapping on his arm, taking off his clothes so he could breathe easier," the man said.
"He was in and out. He didn’t say anything. He was actually mostly unconscious and then he came back and squeezed my hand and his hand – his arm was going cold. But he started breathing again, it seemed like he was going to make it. I thought he was going to make it."
The deputy was taken to Orlando Regional Medical Center, where he later died from his injuries.
"He was the best, he really was," Florida Highway Patrol Sgt. Kim Montes said in an emotional statement. "And I know people say that all the time but everybody knows this guy -- just a loving, wonderful human being."
The driver of the van was not hurt.
Authorities said Markeith Loyd, 41, is accused of firing multiple shots at Orlando police Sgt. Debra Clayton Monday morning, killing her. Loyd remains at large.