SOUTH JORDAN — A South Jordan family is grieving the loss of a recently returned LDS missionary.

Tyler Poulson, 21, was killed Friday night after getting out of a moving pickup truck that was traveling about 35 mph near 10900 South and 1300 West.

Poulson apparently had an argument with two brothers who were in the truck with him, said South Jordan police spokesman Sgt. Dan Starks.

The argument centered around one of the brothers, who had been using profanity, Starks said. Poulson, who felt offended, eventually said he would get out of the truck if it continued. Considering it an empty threat, one of the men told him to do it, Starks said.

There was nothing medical personnel could do to help, Starks said. Poulson had some vital signs and a medical helicopter was dispatched, but his injuries were too extensive to warrant a hospital flight.

Poulson was pronounced dead on arrival at Jordan Valley Hospital, Starks said.

The brother who commented to Poulson about getting out of the truck is devastated, Starks said, and grief counselors are trying to help the family cope.

"I can't imagine how devastating it has to be," Starks said.

Investigators don't suspect drugs or alcohol to be a factor in Poulson's decision, but an autopsy will be performed, Starks said.