Brinkman had also allegedly dated the couple's daughter, Maier said.
Kylie Pifer, 18, was a biology major at the university, according to a message by Thomas Gibson, BGSU vice president for student affairs.
Brinkman, 45, was charged with three counts of aggravated murder, three counts of kidnapping and one count of tampering with evidence in their deaths, North Royalton police said on Wednesday.
Brinkman was arrested early Tuesday after a nine-hour standoff on Valley Forge Drive in Brunswick.
Autopsies were scheduled for Tuesday for the North Royalton victims.
George Brinkman, who had been house-sitting for the couple, was the only person who had access to Rogell and Roberta's home.
Police in North Royalton wouldn't say what kind of relationship, if any, the suspect had with the slain mother and daughters. He noted the relationship was "long estranged".
The sheriff said it appears the only connection among the five is Brinkman.
"We are shocked and grieved by this tragedy, and our hearts go out to Kylie's family and friends", he said.
Before the standoff began Monday night, Brunswick Lt. Steven Hoover said his department was contacted at 7:12 p.m. Monday by the Stark County Sheriff's Office.
Their bodies were found after Rogell's son tried but could not reach them on Sunday after the couple had come home from vacation. OH police say they have taken a homicide suspect into custody after a standoff.
Police officers forced entry into the home this morning and were able to take Brinkman into custody by utilizing a stun gun, police said.
FBI investigators at the Brunswick house Tuesday declined to discuss the case.
The Stark County Sheriff's Office stated it has two arrest warrants for Brinkman and he will be charged with two counts of murder in the deaths of the couple.
An American college student who was released from a North Korean prison is finally home but in a coma and undergoing treatment at an OH hospital.