New details have emerged about two people – including a child – killed when a woman drove a vehicle through a youth soccer game in Kansas, as officials on Monday continued to investigate the cause of the tragedy.

Chris Adrian, a middle school soccer coach, said his family was heartbroken over losing his six-year-old son, Cole, who died after the incident at Wichita’s Stryker Sports Complex in which 10 others were hurt, some seriously.

“Cole was an incredible kid and could put a smile on anyone’s face,” Adrian said in a text message reported by the New York Times.

“He was the joy and light of our community. His pure heart was open to everyone. He had the best laugh. He was a friend with everyone, young or old.”

The other victim, 35-year-old Nicholas Schafer, was identified Sunday.

Schafer and his wife, Ashley, celebrated their 14th anniversary in May, according to a Facebook post, and had three children. An online fundraiser set up by friends said the family had “suffered tremendous loss, immense pain, and devastation, forever changing their futures”.

The two who died were unrelated and described as residents of McPherson, Kansas, about an hour north of Wichita.

A 34-year-old woman from Garden City, Kansas, who was at the wheel of the Chevrolet pickup truck at the center of the case, was released without charges by the Wichita police department on Sunday, pending further investigation and toxicology tests.

According to witnesses, the woman’s vehicle, also containing two of her three children, suddenly drove on to the field, having been parked in a space nearby.

Wichita’s police chief, Joe Sullivan, said in a statement on Facebook that his investigators “will continue working to understand exactly what happened”.

He said: “Our hearts are with the families of [Cole] and Nicholas as they face an unimaginable loss. What should have been a day of children playing soccer and families spending time together ended in tragedy.

“We are also thinking about those who were injured, their loved ones and everyone who witnessed what happened. We know this tragedy has affected many people throughout our community, and we want those families to know they are not alone.”

Those injured, Sullivan said, included five children: two girls ages five and nine, a five-year-old boy, and two boys aged eight.

Also injured were women aged 28, 59 and 65, and men aged 32 and 68. A 61-year-old woman was treated for medical complications unrelated to traumatic injuries.

Police said they have spoken to more than 30 witnesses so far and appealed for anybody with video of the incident to come forward.

Accounts of the tragedy were published on Monday by NBC News, which spoke to several people who were there.

Erica Case said she was watching her nine-year-old son’s game on an adjacent field when she heard an engine revving and several “boom” sounds.

“I saw the truck hitting things,” she said. “I saw debris flying in the air.

“I don’t know if it was a cone, a chair or a person, but you could see matter flying as the truck was barreling through the soccer field at a decent rate of speed.

“The moment that I recognized that that wasn’t gunshots, that that was bodies, I lost it, because it wasn’t just adults. It was also children.”

She said it took emergency services about 10 minutes to arrive, time in which bystanders raced to help those who were hurt. She said she saw one person giving CPR to one of the victims.

David Griekspoor was at the complex with his brother and sister-in-law, watching his nephew play soccer.

“It sounded like small gunfire – bap, bap, bap,” he told NBC. “You look up, and you just see the truck going through a line of people.”

The sports complex was closed for the remainder of the weekend after the incident.

On Sunday night, some members of the Wichita youth soccer community held a vigil and memorial at an indoor sports facility across town.