Police are waiting to identify the gunman until his family has been notified.
The gunman and a maintenance man at the complex, 51-year-old Steve Bailey, were shouting at each other before the gunman opened fire, said Kaysville Police Chief Sol Oberg. Police are still investigating what the argument was about.
The gunman fired multiple shots at Bailey about 2:30 p.m., continuing to shoot after Bailey fell to the ground, Child said. Soon after, a third man, who was not identified, fired at the gunman, though police could not say whether any of the bullets hit him.
Officers arrived and searched the 120-unit complex at 600 W. Mutton Hollow Road, locating the man on the south side, Child said.
Bailey was flown to McKay-Dee Hospital in Ogden in critical condition, with no change in condition by about 9:15 p.m. Friday.
Residents of the complex praised Bailey as a man who was always helping people and offering his support to anyone going through a hard time.
Mandy Giles, whose sister lives at the complex, said Bailey had been working there about five years. He often sang gospel songs as he walked around the complex, and he leads a Bible study on Monday nights that was on hiatus for the summer but would have started up again soon.
He had also recently bought a pre-kindergarten-level Hooked on Phonics for her 1-year-old daughter.
"He's really awesome," said Giles, adding that she hopes he survives. "God's with him."
Clearfield Junior High student Manny Ortiz said he was walking by a park on his way home from school when he heard the gunfire.
"The kids scattered everywhere" as soon as the first shot went off, he said. He counted about 10 shots.
Todd Barnes worried about his 4-year-old son, who was in the Francis Peak View (formerly Tanner Acres) apartment complex with his baby sitter, who lived on the apartment's south side. He was able to get in touch with the sitter over the phone, but he was still concerned.
A short time after police found the deceased gunman, they let people back in to the apartment complex. Barnes' son came running down the sidewalk and was swept up in his parents' arms, safe and sound.