Derek Boogaard NHL Player Found Dead. New York Ranger/Minnesota Wild: How did he die? Concussion Related?

On May 13, 2011, NHL Player Derek Boogaard was found dead in his Minneapolis apartment by family members. He was 28 years old and last played for the New York Rangers. How did Derek Boogaard die?
He was known for being a tough guy type of player. In the old days, maybe he would be considered a goon. He has had several concussions in his playing career and speculation may be that this contributed to his death somehow. Is it similar to the Dave Duerson death? Was it suicide? Brain tissue may be analyzed to see if there was any trauma or damage.

NHL Players Association executive director Donald Fehr also issued a statement:

"The NHLPA is deeply saddened by the sudden passing of Derek Boogaard. Derek was a well-liked and respected member of the NHLPA, and his passing is a great loss to the entire hockey community. Our sincere condolences to Derek's many friends and family during this difficult time." Derek Boogaard RIP.