Police in Novi, Michigan, said the firework tilted slightly and started to fire toward people nearby Sunday night. The 24-year-old Kivlenieks was in a hot tub and tried to get clear with several other people, police Lt. Jason Meier said. Authorities earlier said the Lativan had died of an apparent head injury during a fall, but an autopsy clarified the cause of death.
The fire department and EMTs got to the private home shortly after 10 p.m. and took Kivlenieks to a hospital, where he was pronounced dead, Meier said. The Oakland County Medical Examiner's office reported preliminary autopsy results Monday afternoon.
Prior to the autopsy, police said Kivlenieks was believed to have slipped and hit his head on concrete while running from a malfunctioning firework.
"At the moment, we're pretty certain this was a tragic accident," Meier said.
The Blue Jackets and Latvian Hockey Federation announced Kivlenieks' death, with the NHL club initially saying it resulted from an apparent head injury in a fall. The team's statement made no mention of fireworks.
Columbus general manager Jarmo Kekalainen tweeted: "Life is so precious and can be so fragile. Hug your loved ones today. RIP Matiss, you will be dearly missed." Blue Jackets president of hockey operations John Davidson called it a "devastating time" for the team.
"Kivi was an outstanding young man who greeted every day and everyone with a smile and the impact he had during his four years with our organization will not be forgotten," he said.
"What a tragic loss for all of us who knew him and I am thinking and praying for his family," former Blue Jackets captain Nick Foligno tweeted. "Heaven gained a darn good goalie and better person? Just, way too soon."
Former Columbus defenseman David Savard learned of it from Foligno.
"That was a brutal wakeup this morning," Savard said in French. "That was a good kid with a lot of talent who was going to be a part of the team next year or in the future. That's extremely sad."
Kivlenieks' death came on the eve of Game 4 of the Stanley Cup Final in Montreal, where the Tampa Bay Lightning had a chance to clinch the championship against the Canadiens on Monday night.
NHL Commissioner Gary Bettman said Kivlenieks' "love for life and passion for the game will be deeply missed by all those who have been fortunate to have him as a teammate and a friend."
The Latvian Hockey Federation called Kivlenieks' death "a great loss not only for Latvian hockey but for the entire Latvian nation."
Seeing all the beautiful tributes to Matiss only further cements what kind of person he was! What a tragic loss for all of us who knew him and I am thinking and praying for his family. Heaven gained a darn good goalie and better person… Just, way too soon.
RIP Kivi! https://t.co/k2XWVXmfYE
— Nick Foligno (@NickFoligno) July 5, 2021
Kivlenieks most recently represented Latvia this spring at the world hockey championship in which he played four games. He played two games for the Blue Jackets and eight for the American Hockey League's Cleveland Monsters this past season.
A native of Riga, Latvia, Kivlenieks signed with the Blue Jackets as a free agent in May 2017 and played eight games for the club overall. He was seen as a possible No. 2 goaltender next season if Joonas Korpisalo or Elvis Merzlikins is traded.
Kivlenieks was at Mid-Ohio Sports Car Course in Lexington last Tuesday as a guest of IndyCar driver Alexander Rossi.
Rossi announced that day he was going to race the Baja 1000 in Mexico in November, and Kivlenieks took a ride around Mid-Ohio in a Honda Ridgeline to help promote both Rossi and Sunday's IndyCar race.
"This hits hard," Rossi tweeted. "Prayers to the family and the team."
How the events of Sunday night unfolded came into focus Monday, as Meier said the autopsy findings prompted officers to re-interview some witnesses. He said police will continue trying to interview as many people as they can who were present at the time.
"We're starting to put together a pretty good picture of what occurred," he said.
Meier said police who responded to the emergency calls said there was a "large gathering" at the home but he didn't have an estimate of how many people were there or how many people police want to speak with.
Meier would not provide the address of the property in Novi, a northern suburb of Detroit. A police report hasn't yet been completed.