A Pennsylvania woman allegedly shot a woman she believed was having an affair with her husband, before turning the gun on herself in a gruesome murder-suicide on Monday night.

Jennair Gerardot, 48, is suspected of fatally shooting 33-year-old Meredith Chapman, a former colleague of her husband, Mark Gerardot, with whom he was believed to have an affair with. Mark and Chapman worked at the University of Delaware together before Chapman became employed as assistant vice president at Villanova University.

Police Superintendent William Colarulo said the suspect carried out a premeditated murder: “[Jennair] went to great lengths to disguise herself. She wore a wig, and took a train from Delaware to Radnor. She broke into the victim’s house, and cleaned up the glass so the victim didn’t realize someone was in her home.”

When Chapman entered her house around 7 p.m. EDT Monday, Jennair shot the unsuspecting victim before shooting herself with the same gun. After being alerted about “two subjects found and blood everywhere,” by an unidentified individual, the police arrived at the scene to find Jennair’s body in the kitchen, not far from Chapman’s body. A gun was discovered under Jennair’s body.

There were indications that the jilted lover would carry out such a crime.

“There were emails and text messages indicating what [Jennair] might do,” Colarulo said, New York Post reported.

Jennair’s husband said he was supposed to have dinner with Chapman near her house and when she failed to show up, he went to her house. When the police arrived they found Mark outside Chapman’s house. Mark told the police they might find his wife inside the house.

Chapman, a Republican, also unsuccessfully ran for senatorial office in 2016, against Democratic incumbent Dave Sokola for the 8th District Senate seat.

“It’s very tragic,’’ said Sokola, after hearing about Chapman’s death. “I thought she was very reasonable to talk to. It’s way too young for someone who had a very nice career and new opportunities ahead of her.”

Hours before her death, Chapman, tweeted: “Couldn’t be more excited … just a week on the job and I’m already feeling the love from #NovaNation.”

“Our hearts are broken by the devastating loss of our new colleague, said Villanova spokesman Jonathan Gust in a statement Tuesday. “The thoughts and prayers of the entire university community are with her family, friends and colleagues during this extremely difficult time.”

A spokeswoman for Chapman family said they were “heartbroken and requests privacy and respect as they grieve.”

“She loved her family fiercely, was a compassionate friend and among the most talented and innovative professionals in her field,” the spokeswoman added. “Her death was sudden and tragic, but will not define who she was to the thousands of people who loved her.”

Chapman was married to Luke Chapman, Newark city councilman who recently announced that he would not be seeking a fourth term, reported Pennsylvania radio station WHYY — where Jennair had worked as a reporter/producer in the past.

The University of Delaware also released a statement: “Everyone who knew and worked with Meredith is heartbroken. As a proud alumna of UD, her commitment to her work was exceeded only by her boundless energy. She believed earnestly in the power of communication to bring people together, whether to achieve their collective goals or simply to share their stories. We will miss her.”

Crime Scene A Pennsylvania woman allegedly shot a woman she believed was having an affair with her husband, before turning the gun on herself in a gruesome murder-suicide. In this representational photo, a police officer watches over the crime scene from a nearby corner in Pittsburgh, Pennsylvania, April 4, 2009. Photo: Getty Images/ Ross Mantle