The man found critically injured at his home in Corcoran has died in what family members are describing as a violent confrontation in the home.

Russell Roos said Tuesday that his son, Robert J. Roos, 33, was found lying in the driveway about 9 a.m. Saturday at the family's home in the 10600 block of County Road 116.

The younger Roos was unconscious when officers arrived and was taken to North Memorial Medical Center in Robbinsdale, authorities said.

"There's a crime that took place, yes," said the victim's father, who declined to say anything else.

Kelly Roos, a relative, said in a Facebook posting that Robert Roos suffered "massive trauma to the back of his head" and was pronounced dead Sunday evening.

Hennepin County sheriff's detectives were at the scene Saturday, along with a mobile crime lab, investigating and canvassing the neighborhood through the day. In the three days since Robert Roos was found, the Sheriff's Office has said nothing more than that a "suspicious incident" occurred.

Authorities have announced no arrests.

Stepbrother Adam Mach said Tuesday that family members are being told that it appears that someone entered the home while Robert Roos was alone and some sort of confrontation occurred.

Furniture and other items in the home were found knocked over, Mach said.

"I went to the hospital and saw him," said Mach. "He was brain-dead Sunday morning."

Meaghan Ess Hibbard, a longtime classmate of Robert Roos who graduated with him from Buffalo High School, said she brought flowers to the Roos home Monday and spoke with the victim's mother, Bertha. "'It looked like he put up a quite a fight'" with whoever was in the home with him, Hibbard recalled the mother as saying.

Mach described Robert Roos as a "very smart person, just brilliant." He said his stepbrother attended Stanford University after graduating from high school but didn't have a steady job. Of late, Mach said, Robert Roos was writing computer code for a friend's business and was "also working on [creating] a social network."

Mach said he has been close to his stepbrother since they first met about three years ago and "I don't see that anybody would want to hurt him."

"I just went to the Renaissance Festival with him," Mach said. "It's ridiculous."

Mach said a wake, memorial service and then burial in Iowa are scheduled for later in the week.

Hibbard said her friend, a National Merit Scholar, was nothing short of "a genius. ... I think he would even frustrate his teachers because he was smarter than them."

Paul Walsh • 612-673-4482