Winnabago County Sheriff's Office; Courtesy of Rob Misleh Michael David McKee (left); and Monique Tepe.
Winnabago County Sheriff’s Office; Courtesy of Rob Misleh

Michael David McKee (left); and Monique Tepe.

The arrest of an Illinois surgeon in connection with his ex-wife and her husband’s killings did not come as a shock to the slain couple’s family, a relative says.

Monique Tepe and her husband Spencer Tepe were fatally shot in their home in the dead of the night on Dec. 30 in their Columbus, Ohio home.

Monique’s ex-husband, Michael David McKee, 39, whom she divorced nearly a decade ago, was arrested over the weekend on murder charges.

Now, 37-year-old Spencer’s family says they were not surprised that McKee has been identified as the suspect, given Monique’s alleged history with him.

“Monique was very vocal about being terrified of this guy [till her death],” Rob Misleh, who is married to Spencer’s sister, tells PEOPLE.

“He was very emotionally abusive to her, to the point that it changed her as a person,” Misleh alleges.

Authorities have not explicitly accused McKee of emotional abuse. PEOPLE has reached out to the pubic defender, who is currently representing McKee in Illinois, for comments about the allegations.

It wasn’t immediately clear if McKee had tried to contact Monique, 37, since their divorce in 2017.

Police haven’t publicly commented on a possible motive behind the killings, but an expert tells PEOPLE why an ex might return — even after years of separation — to a former partner’s life.

An ex “may fixate on a narrative that they were wronged or replaced, and over time that grievance can harden,” Jonathan Alpert, a psychotherapist and author of Therapy Nation, tells PEOPLE. “They ruminate, rewrite the past, and build an internal storyline that turns the former partner into the source of their distress.”

“From the outside, there are no obvious warning signs,” Alpert says. “But internally, the offender may have been dealing with a grievance for years, and the new partner or new family can become a trigger because it symbolizes a life they feel cut out of.”

Schoedinger Funeral & Cremation Service Monique and Spencer Tepe.
Schoedinger Funeral & Cremation Service

Monique and Spencer Tepe.

The Tepe family are very “confident” that authorities identified the “right” suspect, Misleh tells PEOPLE.

McKee was arrested in Illinois, where he is based, on Jan. 10. He was initially charged with murder, and the charges were upgraded the following day to aggravated premeditated murder, according to court records obtained by PEOPLE.

McKee is awaiting extradition to Ohio and his lawyer told an Illinois judge this week that he plans on pleading not guilty to the charges.