Keep in mind, since bigfoot is viewed by the mainstream scientific community as a mythical creature, there cannot be any official reports out there of it doing anything. It'd be the equivilent of someone reporting that unicorns are dangerous because someone fell off one once. The only difference being there is a ton of evidence that bigfoot exists, and zero evidence that unicorns are real.
While there are no "official" reports of any deaths attributed to bigfoot, there are several anecdotal "off the record" reports of bigfoot creatures killing someone. Here are a few examples of these reports...
Bigfoot researcher Tim "Coonbo" Baker told a story during an Internet radio show of a first person account he was given by someone who claims to have witnessed a bigfoot killing someone.
Apparently two men, a hunter and a guide, we're in rural Arizona or New Mexico (can't remember which) back in the 80's. During their hunting excursion they sited a bigfoot creature. Evidently the hunter decided to get famous and took a shot at the creature. However, instead of killing it, all it did was piss him off. The creature attacked the men, knocking the hunter's head off with a swipe of his hand. When he turned to the guide, the guide dropped his rifle and backed away, and managed to escape with his life.
The guide reported this event to law enforcement, and took them to the location where it occurred. There was blood scattered about and the hunter's body and severed head were lying there as the witness had reported. Even though huge footprints where everywhere and the witness clearly stated that it was a bigfoot that did it, the law enforcement officer stated at the time that his report would theorize that it was a bear attack.
Coonbo states that he spent some time researching this to see if any official report of the "death by bear attack" had been filed those years ago, but he was unable to locate any such report in the archives of the county where this supposedly took place.
A story from Canada tells of a couple friends who were camping or trapping in the sticks. During their trip they had returned to their campsite on a couple of consecutive days to find that something or someone had gone thru their belongings, opened containers that required hands and fingers to open, and found some of their food had been eaten.
Both men got spooked as it was getting dark and decided to end their trip early. One started packing up camp while the other went to go get their vehicle. When he returned 30 min or so later, he found his friend dead and headless. The victim had finished up packing and was sitting on a log facing the fire, and some kind of creature set upon him, killing him before he could react. The surviving friend seemingly missed the melee by mere minutes. He jumped in his vehicle and left the area, and his camping gear, where it sat.
Brenda Harris of the New Mexico shadow seekers, on the bigfoot outlaws Internet radio show, told the audience about a report she investigated in a small community on the Pueblo reservation earlier this year.
An elderly couple were sitting in their home one day, when a huge sasquatch creature just barged into their house through the front door without warning (or an invitation).
They grabbed brooms and other household implements and tried shooing the creature out of their house, but it grabbed the man and tore both his arms off and beat him to death with his own arm. A few days later a similar event took place a couple blocks away, when another elderly man was attacked and killed in his home by some sort of powerful creature.
Tim "Coonbo" Baker was on that radio show, and after hearing these accounts postulated that it's at least possible that heavy metal run off from those huge epa caused mine spills may be the cause. The mines leaked millions of gallons of polluted water into the river system, and since the rivers there drain into river systems near the Pueblo reservation, this pollution could possibly be the cause for this creature snapping and becoming a murderous monster.
One final story I recall off the top of my head took place in New Mexico. A border patrol officer was thrown off a cliff by what a witness reports to be a tall hairy manlike creature. Altho there was a witness to the death, and it was common knowledge by local border patrol that creatures had been sited prior to this, their official report stated that the cause of the officer falling off the cliff was undetermined.
These are just four or five of dozens of reports I've read and heard about over the years. A Google of the subject and a couple hours of research on you tube might turn up some interesting stories as well.
Native Americans tell scads of stories regarding how they view bigfoot as fellow people, and that these "people of the forest" like to snatch people walking after dark, or sneak into camps and kidnap women and children and eat them or sexually assault them, most never to be heard from again. Some tribes report that agreements were made with the bigfoot people hundreds of yrs ago that if the NA people stay out of certain areas, or give the bigfoot food on a regular basis, they would not steal people from their tribe.
For the most part bigfoot creatures are reported to be skittish and tend to avoid contact with Humans if possible, but they are extremely big, and extremely strong, and can kill a Human with very little effort. Like with Humans and other primate species, even though the vast majority of bigfoot creatures are likely not dangerous, there are those out there with nasty attitudes and murderous dispositions. To this day you still hear stories of how hunters will encounter creatures while in the woods, and that they likely wouldn't have escaped alive if they weren't armed.