Harrison said he doesn't know why Griego decided to come to the church, but that it was like a second home for the homeschooled teen.
"It was a familiar place to him," he said. "I think if he did have in his mindset to do something foolish and start shooting people there also, I think his demeanor was tamed a little bit because he saw people there he knew."
Authorities have said there was no indication Griego intended to harm anyone at the church. The sheriff also said Griego and his girlfriend had spent much of the day together.
A memorial service is planned Friday at the church for victims Greg Griego, 51, his wife, Sarah Griego, 40, and three of their children — a 9-year-old boy, Zephania Griego, and daughters Jael Griego, 5, and Angelina Griego, 2.
On Wednesday night, the church also held an hourlong prayer vigil that drew an estimated 2,000 people.
Pastor Skip Heitzig shared stories about Greg Griego, who also served as a voluntary chaplain at the county jail and provided spiritual guidance for local firefighters. He said Greg was dedicated to helping others find God. Heitzig also urged the crowd to remember that forgiveness and restoration — tenets dear to Greg — will be important as the community moves forward.
Relatives, in a statement Tuesday night, said they were heartbroken, and remembered the teen as a bright and talented musician who played guitar, drums and bass with the church choir. He also was a wrestler who dreamed of following his family's long tradition of military service, and a boy who accompanied his pastor father on rescue missions to Mexico, they said.
Follow Susan Montoya Bryan on Twitter: http://www.twitter.com/susanmbryanNM