A Taurus Tracker .357 Magnum revolver was found at the crime scene, with two of its seven rounds missing.
Investigators believe Gerardot took a train from Delaware to Chapman’s home – while wearing a wig and clothing later found discarded in a bag at the scene -- and broke in through the front door, cleaning up the glass so her target would not notice anything wrong when she came home.
“It’s not a love triangle. You had a man who was married that was having an affair with this other woman,” Radnor Township Police Superintendent William Colarulo said during the news conference.
“The wife knew about it. And this was a calculated, planned attack,” Colarulo said. “She broke into the house. She was lying in wait, and she shot her as soon as she walked in, and then she shot herself.
“There were emails and text messages indicating what she planned to do. Detectives are still sorting that out.”
Flanagan said Tuesday that officers were called to Chapman’s home just after 7 p.m. Monday after receiving a 911 call reporting two people down and blood inside the residence. They were met in the driveway by Gerardot’s husband, Mark Gerardot, who said he believed his wife might be inside the house.
The officers went inside the home and found both women dead in the kitchen.
Flanagan said that Mark Gerardot, 49, told police officers that he and his wife were having domestic problems that also involved Chapman. Investigators said he had been led to believe that Chapman would be meeting him nearby for dinner.
The Courier-Express in DuBois, Pennsylvania, reported that Mark Gerardot was waiting for Chapman to show up when he began receiving disturbing text messages from his wife. He went to Chapman's home because of those messages and found the bodies.
See the entire Radnor Township police news conference, streamed live Tuesday by the News Journal in Wilmington, below.
Chapman's neighbor, Melissa DeJoseph, told the Inquirer she saw the victim drive up between 5 p.m. and 6 p.m. and, with a bag over her shoulder, walk toward the door. A few seconds later, she heard sharp noises from inside the house.
"In my head, I was, like, 'Is that a gunshot? No, it can't be a gunshot,'" DeJoseph told the Inquirer.
Other neighbors also reported hearing the gunshots.
Chapman was married to Luke Chapman, a former Newark city councilman, but they were no longer living together, the Inquirer reported. Luke Chapman announced earlier this year that he would not run for a fourth term in office.
Prior to her position at Villanova, Meredith Chapman served as senior director of marketing for the University of Delaware, where she also got her college degree. She also taught at the university as an adjunct professor.
She worked on several political campaigns, as well as on Capitol Hill, where she collaborated with former Vice President Joe Biden when he was a Delaware state senator, according to her Facebook page. She served as communications manager for then-U.S. Rep. Mike Castle in 2007 and 2008, the News Journal reported.
Chapman ran unsuccessfully for a Delaware State Senate seat in 2016, losing the election to opponent Dave Sokola.
Sokola expressed shock at the news of Chapman’s slaying.
"Kathy and I are stunned by the news about Meredith and I'm deeply, deeply saddened to learn that such a promising young woman's life has been cut so short," Sokola wrote on Facebook. "I've always respected my opponents and Meredith was certainly no exception. She was sharp, hard-working and motivated by a sincere desire to serve her community. She was bound for great things and it's tragic for that light to go out so soon.
“I’ve also had the privilege to work with her husband, Luke, over the years, and he especially is in our hearts today. We wish him strength, peace, and privacy in what we know is an incredibly difficult and painful time."
Like Sokola, Chapman’s friends expressed shock on social media.
“I’m absolutely floored,” Richard Wisk wrote. “Meredith, RIP, you will be missed tremendously.”
Colleen Auer-Smith described Chapman as a bright light and a “ray of sunshine.”
“Why of all people? I don’t understand,” Auer-Smith wrote.
A family spokesperson described Chapman as a "beacon of light" to all who knew her in a statement obtained by the News Journal.
“She loved her family fiercely, was a compassionate friend and among the most talented and innovative professionals in her field,” the statement read. “Her death was sudden and tragic, but will not define who she was to the thousands of people who loved her. Her family is devastated, heartbroken and requests privacy and respect as they grieve.”
Mark Gerardot worked as a creative director at the University of Delaware until earlier this month, when he left that position. Before her move to Villanova University, Chapman was his supervisor, the News Journal reported.
He and his wife also previously ran their own marketing and design company, the Inquirer reported.
Jennair Gerardot also spent five years as marketing manager for a South Carolina-based marketing company, Circor Instrumentation, before leaving that job in December.
According to a post she wrote on the NextDoor neighborhood app in February, she left her position at Circor because of her husband’s new job at the University of Delaware.
The Inquirer, which tracked down Gerardot's post, reported that she went on NextDoor pleading for help with her marriage.
"I just transferred to Delaware in December for my husband's new job, and he's telling me he wants a divorce," she wrote, according to the newspaper. "I don't know anyone and am completely clueless to the area."
She asked for a recommendation for a reputable, successful and driven divorce lawyer.
Gerardot returned to NextDoor in March.
“Please recommend an EXCELLENT marriage counselor for couple on the brink of divorce,” she wrote.
The Inquirer reported that the posts did not make clear whether the couple ever sought counseling.