The father of Cole Adrian, a six-year-old boy killed when a woman drove through a soccer game at a park in Wichita, Kansas, on 17 October, paid an emotional tribute to his son at his funeral service on Monday.

Chris Adrian, of McPherson, Kansas, spoke through tears while he remembered Cole as an energetic, fun-loving child who loved life and “captured the heart” of everyone he met.

“Cole often told us this was the ‘best day ever’, even on days when nothing really special happened,” Adrian said during the eulogy, which was livestreamed. “He found joy in the simplest things, and had a way of making ordinary days feel extraordinary.

“The world would be a much brighter place if we all had a little bit more of Cole’s heart.”

The service for Cole at McPherson Free Methodist church was his family’s farewell to one of two victims from the tragedy at the Stryker Sports Complex that remains under police investigation.

Nicholas Schafer, 35, a soccer coach and middle school teacher also from McPherson, about an hour north of Wichita, was also killed when a pickup truck with a 34-year-old woman at the wheel reportedly sped from a parking lot and across the pitch where a game was under way.

Ten other people were injured, including girls aged five and nine, two boys aged eight, and one five-year-old boy.

The suspected driver, from Garden City, Kansas, who reportedly had two of her own children in the car with her, according to police, was arrested at the scene. She was released a day later without charges pending further investigation, including the results of toxicology testing as well as an examination of her truck.

At Monday’s service, Adrian said the family had taken comfort from the support of the Wichita youth soccer community, whose players wore tribute shirts bearing the letters “LLCA” at a game days after Cole’s death.

“At first, we didn’t know what it stood for,” he said, clutching the hand of his wife, Natalie, Cole’s mother.

“And so we sat up there in the press box, and it was ‘laugh like Cole’ – oh no, no, it could be ‘love like Cole’, ‘live like Cole’, ‘long live Cole’.

“Every one felt perfect. They’re more than words on a shirt now. They’re a reminder of who Cole was, and who we can all strive to be.”

Adrian said his family also leaned heavily on their Christian faith.

“Monday morning, there was a double rainbow over our town of McPherson – and for me, it was an answer, it was a promise, it was a reminder from heaven that Cole and Nick are there together, and that someday we will see them again,” he said.

“We miss Cole more than we could ever express, and there are no words that can make this hurt less. There’s no pep talk that can make any of this make sense or be OK. There’s one thing that brings us comfort, that last week Cole ran through those gates of heaven just like we’ve seen him run across that soccer field so many times.

“I could see him running full speed, wrapping his arms around Jesus and giving him one of those famous squeeze hugs. Saying those words we were so lucky to hear so many times: ‘best day ever’.”

Investigators have urged the public to be patient as they continue to work through the circumstances of case in search of a cause.

Wichita’s police chief, Joe Sullivan, released a statement defending the release of the driver the day after the tragedy.

“We know that this case has captured the attention of people all over the country, and many of those people have strong opinions even though they do not have direct knowledge of what occurred,” he said, as reported by Kansas NPR affiliate KCUR.

“We recognize that the decision the law and constitution required us to make on [18 October] may not be popular. We swear an oath to support the laws of the state of Kansas and the constitution of the US, and no one in the Wichita police department takes that oath for granted.”