Will Corporon issued a statement saying his father, Dr. William Lewis Corporan, and nephew, Reat Griffin Underwood, were killed in Sunday's attack outside a Jewish community center in Overland Park.
The family is Christian.
Authorities haven't released the name of a woman or girl who was killed minutes later in an attack at a Jewish retirement community a few blocks away.
Police arrested a man in his 70s after the shootings. They haven't released his name but have said they don't think he knew the victims.
Police have declined to say if they think the attack was motivated by anti-Semitism.
OVERLAND PARK, Kan. — A man in his 70s opened fire Sunday outside of a Jewish community center and nearby retirement community, killing three people, authorities said.
Overland Park Police Chief John Douglass said at a news conference Sunday evening that a person who had been reported to be in critical condition earlier was among three killed in the attacks, which apparently occurred minutes apart.
"Today is a sad and very tragic day," Douglass said. "As you might imagine we are only three hours into this investigation. There's a lot of innuendo and a lot of assertions going around. There is really very little hardcore information."
Shots were fired behind the Jewish Community Center of Greater Kansas City in a parking lot about 1 p.m., Douglass said. One male died at the scene, another male died at a hospital. The gunman then fled and opened fire at nearby Village Shalom, killing a female, before later being arrested near an elementary school. Two other people were shot at, but the gunfire missed them, Douglass said.
Douglass said it was too early in the investigation to determine if the shootings were hate crimes. The Jewish festival of Passover begins Monday. KSHB in Kansas City is reporting that the man was heard yelling "heil Hitler" as hew as taken into custody
"We know it was a vicious act of violence, and we know obviously it was at two Jewish facilities. One might make that assumption," Douglass said.
He described the suspect as a white man in his 70s who is not from Kansas. He said the suspect is being held at the Johnson County Detention Center, but did not provide further information.
"We have no indication he knew the victims," Douglass said, adding that the suspect was not known to Kansas City-area authorities before the shootings. Douglass said a shotgun was used, and investigators were trying to determine whether a handgun and assault-style rifle also were involved.
The Jewish Community Center of Greater Kansas City in Overland Park posted on its Facebook page Sunday afternoon that a "shooting incident" happened near its White Theater entrance.
"Everyone participating in JCC programming has been released to their homes," the center posted later Sunday.
There was a heavy police presence at the campus, which spans several acres in an affluent area of Johnson County, Kan. Police had also taped off the entrance to Village Shalom on Sunday afternoon, and several patrol cars and a crime scene unit van were parked in front.
St. Louis resident Kristy Straeb, 47, said her sister-in-law Stacie Ventimiglia was at the center's pool with a friend and four little girls under the age of 7 for a swimming lesson, which ended about 12:45 p.m. Straeb said they decided at the last minute to get the girls showered.
"They had just gotten the four babies naked, and somebody yelled into the family locker room, 'We have an active shooter situation. You need to get safe,'" Straeb said.
The women got into a cubby area and were "ready to push the little girls into 4 empty lockers," Straeb said. She noted that the women and their children were not harmed and left the center about 2:45 p.m. Sunday.
Auditions for the KC SuperStar competition were scheduled to be held Sunday at the Jewish Community Center. On Sunday afternoon, the website for KC SuperStar, which is a singing competition for high school students, said the auditions were cancelled.