OLATHE, Kan. -- A man accused of fatally shooting three people at Jewish sites in Kansas declared "Heil Hitler!" and asked how many Jews he had killed after the attacks, a police officer testified Monday during a hearing in which the man's apology to some survivors was rejected.

Frazier Glenn Miller, 74, is charged with capital murder in the April 13, 2014, shootings at the Jewish Community Center of Greater Kansas City in Overland Park, Kansas, and at a nearby Jewish retirement home. None of the victims was Jewish.

Prosecutors plan to seek the death penalty.

At a preliminary hearing to determine if there is enough evidence to put Miller on trial, Overland Park police Sgt. Marty C. Ingram, who was working off-duty at the Jewish Community Center, testified that he heard shots and saw the doors of the centre's theatre shatter. He said he took cover as more shots hit the building's facade.

Miller is accused of killing Dr. William Lewis Corporon, 69, and his 14-year-old grandson, Reat Griffin Underwood, who were attending a singing contest audition at the Jewish Community Center.

Ingram found Corporon and his grandson, who was barely alive, outside in a truck.

When he heard that a suspect had been arrested nearby, Ingram accompanied some witnesses to the arrest scene to determine if they could identify him. As they approached the patrol car where Miller was detained, he shouted "Heil Hitler!" and asked how many Jews he had killed, according to the officer.

Another police officer, Charles Wimsatt, testified that Miller tried to recruit him to his cause, asking him if he was German.

Miller, of Aurora in southwest Missouri, is also accused of killing 53-year-old Terri LaManno, who was visiting her mother at a nearby Jewish retirement home.

Miller, who has emphysema and needs oxygen from a tank to breath, muttered during breaks in the hearing about how Jews "owned Hollywood."

Thomas Bates, a former combat medic who worked at the community centre, said he grabbed his medical kit when he heard about the shootings. When he reached the victims, Corporon was dead but Reat was still breathing. Bates said the teen had been shot in the head and there was little that could be done for him.

As court adjourned Monday, Miller turned to LaManno's family, apparently assuming they were Reat's relatives, and apologized.

The family told Miller they didn't accept the apology. They declined a request to be interviewed.

Paul Temme testified that he was getting his gym bag from his car when he heard gunfire. He dialed 911 and chased the shooter's vehicle in a failed attempt to get his license details. But then the shooter stopped.

In phone calls to The Associated Press, Miller has said he thought he was dying because of his emphysema and felt he was fulfilling a patriotic duty by killing Jews. He regretted shooting the teenager, who he said looked older.

Miller, a Vietnam War veteran also known as Frazier Glenn Cross, founded the Carolina Knights of the Ku Klux Klan in his native North Carolina and later the White Patriot Party.