Witnesses say a man who was being pursued by police in Parleys Canyon on Sunday was reckless, out of control and possibly even suicidal.

The man died after crashing into a large tanker truck. Some bloggers on the Internet Monday praised police for stopping the man before any innocent victims were hurt, while others questioned whether the chase should have been called off earlier because of the risk to other motorists.

The Salt Lake County Sheriff's Office is conducting an outside, third-party investigation into the crash, while the Summit County Sheriff's Office said it would review its high-speed pursuit policy, as is standard in any chase.

Summit County Sheriff Dave Edmunds noted, however, this was more than just pursuing a simple fraud suspect. Once the man refused to pull over, the situation was elevated to a felony crime.

"What's the alternative? If you fail to pursue you're sending a message to the criminal element that you can do your crime and go about your business," he said. "I feel very strongly that when people fail to yield, there's a reason for that. What exactly that guy was running from, I don't know yet. It's possible he was involved in a much more serious crime."

The incident began about 2:40 p.m. Sunday when the sheriff's office received a call from a person reporting a possible fraud. Dispatchers broadcast the make and license plate of the car reportedly involved, and a deputy spotted it on I-80. He tried to pull the vehicle over, but the driver kept going, Wall said. Speeds at that time were between 50 and 70 mph.

Near the Salt Lake County border at the summit of Parleys Canyon, the driver dramatically increased his speed going down the canyon, reaching at least 100 mph and weaving in and out of lanes, said Summit County sheriff's detective Josh Wall.

At Lamb's Canyon, the man made a U-turn in the median, went back up the canyon, got off at the Kimball Junction exit and then got right back on the freeway and headed down the canyon again.

This time, the driver made it to the quarry exit before again turning around and heading back up the canyon. By this time, other Summit County deputies and Utah Highway Patrol troopers were assisting in the chase.

Near the summit again, deputies tried to stop the vehicle with road spikes, but the man swerved to avoid them, losing control of his car in the process. The vehicle spun around and headed west in the eastbound lanes, then hit a deputy head-on, Wall said. The deputy suffered shoulder and arm injuries.