An ex-FBI agent suggested a years-long “deep-seated resentment and hatred” was to blame for the tragic murder of an Ohio dentist and his wife — as the two were gunned down just two weeks after their fifth wedding anniversary.

Spencer Tepe, 37, and his wife, Monique, 39, were found dead in their Columbus home on Dec. 30 soon after celebrating their anniversary, authorities said.

The wife’s ex-husband, Michael McKee — a 39-year-old doctor from Chicago — has since been charged with their murders.

Mugshot of Michael David McKee.

Monique’s ex-husband, Michael David McKee, 39, was arrested after the murders.FOX News

McKee is due to face an Illinois court later Monday ahead of his potential extradition back to Ohio to face the charges.

Authorities haven’t yet disclosed a possible motive for the slayings, but a former FBI official speculated resentment could likely be to blame.

“They were married for such a brief time,” the former agent, Jennifer Coffindaffer, told NewsNation.

“That is strange, but I think it was a deep-seated resentment and hate that just built up and finally came to this conclusion.”

Michael and his first wife on their wedding day.
Monique and Michael McKee were married in 2015.Facebook/Phyllis WilliamsMcKee’s short-lived two-year marriage to Monique ended in 2017 when she filed for divorce. Still, court records indicated the divorce was amicable.

Monique married her second husband on Dec. 13, 2020, according to the couple’s obituary.

The slain couple had two kids together.

The two children –  a 4-year-old daughter and 1-year-old son — were found unharmed inside the home when cops discovered the Tepes’ bodies.

The violent attack happened between 2 and 5 a.m. in the upstairs of the home, cops said.

No gun was discovered at the scene, and there was no sign of forced entry.

Spencer Tepe and Monique Tepe smiling and embracing.
Spencer Tepe, 37, and Monique Tepe, 39, were reportedly killed one month shy of their fifth anniversary.Gofundme

Eerie surveillance footage released by authorities showed a “person of interest” walking down an alley near the couple’s home around the time of the killings.

Coffindaffer, the former federal agent, speculated that the killer had likely staked out the home and obtained the passcode to unlock the door.

“They had staked out the location well. It was also very clear they knew where the camera locations were because they evaded a lot of camera coverage, it would seem,” she said.

Spencer Tepe and Monique Tepe on their wedding day.
Spencer Tepe and Monique Tepe on their wedding day.ABC 6

Authorities zeroed in on the alleged killer after tracking a vehicle that was in the vicinity at the time and later left for Rockford, Illinois.

The car was allegedly owned by McKee, police said.

McKee attended medical school at Ohio State University, holding medical licenses in both Illinois and California and living in various states since 2020, including Virginia, Nevada, and Illinois, public records show.

He worked as a vascular surgeon in a practice in the Rockford area.