Doyle said the suspect had "looked a little out of place".
The attack on New Life's worshippers has come as a devastating shock to the prominent megachurch. The church had been recovering from last year's alleged sex-and-drugs scandal between the church founder and head pastor, the Rev Ted Haggard, and a male prostitute and was on a "new course" with their new senior pastor, the Rev Brady Boyd.
"Everybody's just so happy about the direction ... of the church and really excited," Boyd previously told CNN.
Sunday's shooting came "clear out of the blue", Doyle said.
"The amazing thing is ... look how God was preparing the church for this," Boyd highlighted. "Pastor Jack Hayford (The Church on the Way in Van Nuys) had just spoken from California and he talked about giving your fears over to God and not being afraid and giving them all over to Jesus.
"And then minutes later, this arose."
Police are still investigating links between the two shootings and have yet to release details.
"Until we have evidence which conclusively ties these two events together, Arvada police will continue to follow all leads," Arvada Police Chief Don Wick said.
The earlier incident at the YWAM centre occurred at about 12:30am Sunday. YWAM director Peter Warren said the suspect asked whether he could spend the night at the centre's dormitory. When told he could not stay, the man opened fire and then left on foot, Warren said.
Witnesses had described the gunman as a 20-year-old white male, wearing a dark jacket and skull cap.
The victims of the shooting in Arvada were identified as Tiffany Johnson, 26, and Philip Crouse, 24. Both died in surgery after the shooting. Two other wounded victims surviving the first attack are Dan Griebenow, 24, who remains in a critical condition, and Charlie Blanch, 22.
YWAM - which has 1,100 locations - trains people ranging from their late teens to their seventies in a 12-week course that prepares them to be missionaries. The Arvada centre trains about 300 people a year.
