A family spokesman, police and hospital representatives are expected to speak Monday morning at a news conference about Sunday's shooting.
Witnesses say they heard one gunshot during the 11:30 a.m. Mass at Saint James the Just Catholic Church, and that parishioners immediately hit the floor.
The victim was taken to McKay-Dee Hospital in Ogden, where he was listed in critical but stable condition.
Investigators say 35-year-old Charles Richard Jennings Jr. was captured Sunday afternoon in nearby Box Elder County after fleeing in a stolen pickup truck.
Parishioners say the victim was the gunman's father-in-law.
Copyright 2013 The Associated Press.