The cause of death was unknown until an autopsy could be completed. Friday, the Hennepin County Medical Examiner ruled that Boogaard's death was caused by an accidental mixture of alcohol and oxycodone, according to the Minneapolis Star Tribune.
Oxycodone is a painkiller typically prescribed to treat severe pain. It can be addictive and like many drugs, can prove fatal if mixed with alcohol.
The New York Post reported last Saturday that Boogaard was in the NHL/NHLPA Substance Abuse and Behavioral Program at the time of his death.
In the days since Boogaard's passing, his family has announced they will donate his brain to researchers at Boston University who study degenerative disease in athletes. In March, those same researchers found traces of CTE, chronic traumatic encephalopathy, in the brain of former NHL enforcer Bob Probert, who passed away last summer.
The Boogaard's and the NHLPA are expected to release statements later Friday.
UPDATE: Here's the statement released today by the Boogaard family:
"We would like to express our appreciation for the outpouring of love and support for our family during this difficult period as we grieve the loss of Derek — our son and brother. We are deeply saddened by this unimaginable loss, but we are grateful for the expression of support that has given us strength as we go through this tragic time.
It is very comforting for our family to know that, while Derek's life was far too short, he had a great impact on many people who he came into contact with. We are proud that Derek was able to live his boyhood dream to play in the National Hockey League. We are even more proud of the fact that Derek was dedicated to making a difference in his adopted communities of Minnesota and New York City, through his countless hours of charitable work.
Earlier today, we received the results of Derek's toxicology report at the time of his accidental death. After repeated courageous attempts at rehabilitation and with the full support of the New York Rangers, the NHLPA, and the NHL, Derek had been showing tremendous improvement but was ultimately unable to beat this opponent. While he played and lived with pain for many years, his passion for the game, his teammates, and his community work was unstoppable.
Our family would like to like to thank the New York Rangers, the Minnesota Wild, the National Hockey League Players' Association, and the National Hockey League for supporting Derek's continued efforts in his battle.
Derek will be greatly missed and will never be forgotten by his fans, friends, and teammates, and especially by us — his family. We respectfully ask for continued privacy as we grieve the loss of Derek."
- Derek Boogaard