Dr. Mailliez, a medical doctor, was the physician who treated the princess at the accident scene. At the time, he wasn't even aware of whose life he was trying to save.
"She couldn't say anything. As soon as I arrived, she was unconscious," Dr. Mailliez says.
While many have wondered whether Diana could have been saved if she had been taken to a hospital sooner, Dr. Mailliez is doubtful.
"It has been a very big question," he says. "But we checked with a lot of surgeons and another medical expert...we couldn't have done anything better. Even if the accident had happened in front of the hospital, she wouldn't have been saved."
Butt says that he doesn't remember seeing any photographers standing near the car just after it crashed.
"When we came into the tunnel, I saw a light smoke," he says. "The spinout of the car just happened."
"I don't remember anyone with cameras at that point," Butt recalls. "That developed in the moments following - three or four minutes after Dr. Mailliez was helping Princess Diana and there was also a volunteer fireman helping the bodyguard in the front seat."
He estimates that he and Dr. Mailliez arrived at the scene less than one minute after the impact.
Although Dr. Mailliez has been questioned by authorities, he said they did not indicate what kinds of answers they sought in their ongoing investigation of the crash.
Butt says that much of what has been reported about Diana's death over the past year have been leaks.
"A lot of books have been written that raise a lot of questions. The way the investigation is going and the judges, they are not releasing a lot of information," he says.
While the investigation continues, authorities are awaiting a report on the damage done to the Mercedes the princess was riding in. That information may not come until late this year, and the full investigation could take another year to complete.