ZEPHYRHILLS, Fla. - Pasco Sheriff's office Detective William Lindsey says the video was hard to watch.
"Because I was called out that night, and I was on the scene where the bodies were recovered and seeing the result."
He says the helmet camera footage shows the two men jumping from a plane at more than 13,000 feet.
It was an instructional jump, but from what Lindsey saw in the video, he says something went wrong with student Andrimar Pordarson. He appeared to lose consciousness.
"It did not appear that he was attempting to open his own parachute," said Lindsey.
As Pordarson fell to earth at 120 miles an hour, instructor Orvar Arnarson tried to save him.
Click here to listen to the 911 call for help
"He was attempting to stabilize the student and reach for the student's rip cord," said Lindsey.
The pair had back-up chutes that deployed, but the two came down hard into trees before hitting the ground.
Sky Dive City's general manager says it's hard to know why the instructor didn't pull his own cord in time.
"You are not paying attention to altitude you are paying attention to getting the job done, but just trying to get a canopy over their head. And it sounds like he waited a little too long to do that," said T.K. Hayes.
As for Arnarson, his MySpace page is filled with pictures of his skydiving exploits. And under his heroes, it says 'good people who enjoy life.'
Now investigators are saying he gave his life trying to save another.
"He was a hero. He died a hero," said Lindsey.
The Sheriff's office says the victims' families back in Iceland have been begging them not to release the video and it appears the law is on their side.
Florida state statute 406.136 says 'a photograph or video or audio recording that depicts or records the killing of a person is confidential and exempt.'
"If I was in their (victims' families) shoes, if I was I had to be in their suffering and pain I would not want this video going viral," said Pasco Sheriff Chris Nocco.
"Death is a personal thing, having the video out there on YouTube of television network or anything. It serves no purpose," said Hayes.
Hayes says it's very unusual to lose conciseness during a free fall. But detectives will meet with the FAA later this week to go over the video again and look at the parachutes.