On Friday morning, Ted DeMers was driving down a leafy street he knew well, in a rural town in northeast Connecticut, when he spotted a young man on foot wearing a motorcycle helmet. Mr. DeMers stopped to speak to him and the man climbed into his vehicle.
Moments later, the young man fatally attacked Mr. DeMers, 62, with an edged weapon and seriously injured a neighbor who tried to help, the police said.
The young man, Peter Manfredonia, 23, a senior at the University of Connecticut, fled and broke into a nearby home and held the homeowner captive before stealing his guns and a truck, the police said.
On Sunday, he drove to an acquaintance’s house about an hour away and killed him, too, before kidnapping another person, stealing a car and driving to New Jersey. There he released his captive, abandoned the vehicle and fled alone into Pennsylvania, where he was last seen on foot in the Poconos region.
Now, the F.B.I. and state authorities have embarked on a sprawling, multistate manhunt for Mr. Manfredonia as investigators continue to make sense of a spasm of violence that has stunned the area and left two families devastated.
The authorities believe that Mr. Manfredonia, last seen on Sunday afternoon, is still armed and dangerous.
Michael Dolan, an attorney representing the Manfredonia family, said that Mr. Manfredonia has struggled with mental health issues for several years and had worked with a number of therapists.
“They’ve asked me to begin by expressing their condolences to the families of those who have suffered,” Mr. Dolan said. He added, “Peter, if you are listening, your parents, sisters and entire family love you. You have their complete and total support. No one wants any harm to come to you or anyone else,” he continued. “They are begging you to surrender so they can help you through this process.”
Mr. DeMers lived in Willington, a small town about 30 minutes northeast of Hartford, near the campus of the University of Connecticut. He was driving from his home, where he had a basement woodworking workshop, to his barn, where he stored wood and other supplies, when he saw a young man walking in the opposite direction. They exchanged words, his son Christopher DeMers, 34, said.
“He ended up on my father’s four-wheeler and my dad gave him a ride back to the end of the road,’’ Mr. DeMers said, explaining that his mother witnessed the man and his father together from the DeMers home, which is just a few hundred feet away from the barn.
Less than 10 minutes later, a neighbor started honking and flashing his car’s lights outside of the house. The neighbor told Mr. DeMers’s wife, Cynthia DeMers, to bring ice because her husband was in “rough shape,” Christopher DeMers recalled.
When Ms. DeMers and the neighbor arrived at the scene, it was grisly: Ted DeMers had injuries to his head, leg and arm and was bleeding profusely, Christopher DeMers said.
“My mom tried to tourniquet his arm and stopped the bleeding on his leg,” he said. “She watched him die.”
Another neighbor, whom the police did not identify and who had tried to intervene, was also bleeding. Mr. Manfredonia and his motorcycle were gone.
Ms. DeMers said state police detectives told her they believed Mr. Manfredonia had been on their street because he had been stalking a neighbor’s daughter.
Later, Mr. Manfredonia broke into a house in Willington and held the owner of the house against his will for almost two days, according to the police and The Hartford Courant. Early Sunday, he stole pistols and long guns from the house, the police said, and took off in the owner’s truck toward Derby, a small city just outside New Haven.
He abandoned the stolen car in a state park. After finding the car, the authorities learned that Mr. Manfredonia had an acquaintance, Nicholas J. Eisele, who lived nearby.
When officers got to Mr. Eisele’s house in Derby, they found him dead. The medical examiner’s office still hasn’t determined how Mr. Eisele, 23, was killed. The Times has not been able to reach his family for comment.
After kidnapping another person from Mr. Eisele’s home, Mr. Manfredonia drove off in a black Volkswagen Jetta. As officers scoured the scene in Connecticut, the police in New Jersey found the kidnapped person, unharmed, in Paterson, N.J.
The individual identified Mr. Manfredonia as the captor, according to the police, who did not identify the kidnapping victim for safety reasons. The Hartford Courant identified the person as Mr. Eisele’s girlfriend.
Authorities said they found the black Volkswagen in New Jersey near the Pennsylvania border. The police said he used “a different form of transportation” to travel to East Stroudsburg, a small borough in the Poconos area in Pennsylvania.
He was last seen around there on Sunday afternoon, wearing a white T-shirt and dark-colored shorts, and carrying a large duffel bag, according to a photograph distributed by the Pennsylvania State Police.
Mr. Manfredonia graduated in 2015 from Newtown High School, which is in the same Connecticut town where the Sandy Hook Elementary School massacre took place in 2012.
Late last year, he posted a photo of himself on Instagram in which he said he had completed a triathlon to raise money for Sandy Hook Promise, a nonprofit group that works to protect children from gun violence.
He started at the University of Connecticut in the fall of 2015, and is a senior enrolled in a joint business and engineering program. He is not taking summer courses and had not lived on campus in recent semesters, according to Stephanie Reitz, a university spokeswoman.
“The university expresses its deepest, most heartfelt sympathies to the victims and their families in this horrible, incomprehensible tragedy,” she said in a statement. “They are all in our thoughts.”
Ted DeMers, who was born in Hartford, Conn., had lived with his wife in a ranch-style house in Willington for the last 32 years.
A furniture salesman-turned woodworker, Mr. DeMers would spend hours building wine and kitchen cabinets, “cool artistic” pieces, and had recently started clearing walking trails on the family’s property, recalled Christopher DeMers, who added that his father was excited about becoming a grandfather.
Mr. DeMers’s friends have set up a GoFundMe page to help his wife with the family’s finances. His family expects to hold a service for him before the end of the summer if social distancing restrictions are eased, his son said.
“He joked about being buried on the property,” his son said. “He wanted his ashes spread on the land that he had.”