About 40 people gathered Tuesday evening in West Valley City, The Salt Lake Tribune reported. The group in West View Park included relatives, friends and people who did not know the Powells.
Josh Powell moved back to Washington state with his sons after his wife, Susan, disappeared in December 2009. He is suspected of killing her, but police never found her body or enough evidence to charge him.
On Feb. 5, 2012, after losing custody of his sons to Susan's parents, Powell killed the boys and himself, setting fire to his rented house in Graham, Wash.
Diane Bellistown of West Jordan, Utah, said she met Susan Powell once at church and did not know the boys. But she was at Tuesday's vigil.
"It's really sad what happened to the family, that the dad could do what he did," she said.