Two robbers broke into his home and demanded money, police say.

A 99-year-old man's death has been ruled a homicide by the Hennepin County Medical Examiner's Office.

The examiner determined that John "Jack" Mathias Gosche died of "sepsis complicating blunt force injuries of the left arm." Gosche had been injured by robbers during a home invasion at his residence in the 4100 block of Colorado Avenue North in Crystal on Dec. 2.

Gosche's arm was injured by the two men who invaded the home and "physically forced" him around the house in search of money, Crystal Police Department explained in a release.

No weapons were involved, but Gosche was transported to the hospital for treatment the day of the crime and four days later he was rushed back to North Memorial Health Hospital's emergency room due to complications from the injury.

He died in the ER from sepsis, the medical examiner ruled.

“We have and will continue to work tirelessly to solve this case and get justice for Mr. Gosche and his family,” Crystal Police Chief Stephanie Revering said.

Anyone with information about the incident is asked to call the Crystal PD at 763-531-1020.

Mayo Clinic describes sepsis as follows: "Sepsis is a potentially life-threatening condition caused by the body's response to an infection. The body normally releases chemicals into the bloodstream to fight an infection. Sepsis occurs when the body's response to these chemicals is out of balance, triggering changes that can damage multiple organ systems."