People lit candles in an Oak Creek park and stood together in solidarity.
The Sikh American community called for a national moment of silence on Sunday.
A posting on the Sikh American Legal Defense and Education Fund's website asked for observances at churches, mosques, synagogues and other places of worship. It said the community hopes such a gesture "will send the message of blessings for all, and that we stand united against hate and intolerance and as part of a common humanity."
Bernard Zapor -- the Bureau of Alcohol, Tobacco, Firearms and Explosives special agent in the investigation -- said Monday that the 9mm semiautomatic handgun with multiple ammunition magazines used by the attacker had been legally purchased.
Page bought the gun on July 28 at the Shooters Shop in West Allis, Wisconsin, and picked it up two days later. The shooter bought ammunition there and used the shop's range.
Shop manager Eric Grabowski and owner Kevin Nugent told CNN Tuesday that surveillance video of Page buying the gun and using it in the range two days later has been turned over to investigators. The suspect did not exhibit unusual behavior while in the store, Grabowski said.
The magazine for the handgun holds at least 17 bullets.
According to a man who described himself as Page's old Army buddy, the attacker talked about "racial holy war" when they served together in the 1990s. Christopher Robillard of Oregon, who said he lost contact with Page more than a decade ago, added that when Page would rant, "it would be about mostly any non-white person."
Page, born on Veterans Day in 1971, joined the Army in 1992 and left the service in 1998, according to Army spokesman George Wright. Page's service was marked by "patterns of misconduct" and he received a general discharge due to "discreditable incidents," according to a Pentagon official. Robillard said Page was pushed out for showing up to formation drunk.
John Tew, manager of a Harley-Davidson motorcyle store in Fayetteville, North Carolina, told CNN he fired Page from his parts coordinator job in 2004 because Page "had a big problem with authority" and with working with women. Tew said he found an application for the Ku Klux Klan on Page's desk the day he was dismissed.