Suffolk County Police Commissioner Geraldine Hart said during a news conference Friday that Campbell's mother called 911 around 2:30 p.m. Thursday to report that her daughter, who was on another line, was threatening to kill her daughters and herself.
"During the conversation, Tenia indicated that the girls were already deceased," Hart said.
Police officers from multiple precincts and departments began a massive search for Campbell and her daughters, who were ultimately found by East Hampton police officers at the entrance to Montauk County Park, Hart said. Montauk is about 65 miles from Medford.
Campbell had parked her minivan near the park’s entrance and walked to the highway, where she “started screaming at officers to shoot her,” the commissioner said.
"During this chaotic time, the officers took her safely into custody and located the girls in the car seats, in the vehicle," Hart said. "Both were in cardiac arrest."
Officers began CPR and paramedics rushed the twins to Stony Brook South Hampton Hospital, where they were pronounced dead.
Newsday reported that the girls' bodies showed no outward signs of trauma. Autopsies were scheduled to determine their cause of death.
"What happened yesterday is incomprehensible," Suffolk County executive Steve Bellone said Friday. "Those two girls, Jasmine and Jaida, those beautiful young girls who lost their lives yesterday. Today in Suffolk County, our hearts are broken."
Newsday reported that court records show Campbell called her mother, Vanessa McQueen, in a frantic state Thursday, saying she had killed the toddlers "with (her) bare hands."
"All Tenia would say was that it's too late. 'I killed my babies and now I have to be with them,'" McQueen told police, according to the documents. "At one point, she said she was going to find the ocean and walk into it and drown so she could be with her babies in heaven."
Montauk County Park, where Campbell and the girls were found, is within a short walking distance of Lake Montauk and Block Island Sound.
When McQueen called 911, a dispatcher was able to patch in with Campbell, who was "hysterical" during their 12-minute conversation, Newsday reported. Campbell told the dispatcher Jasmine and Jaida were dead but refused to give the location where she and the twins were.
Watch Suffolk County officials talk about the arrest of Tenia Campbell below.
An Amber Alert was issued and alerts were placed through local police agencies on Campbell’s license plate number, the newspaper reported. Campbell was located around 4 p.m., about 90 minutes after her mother called 911, through the GPS coordinates of her cellphone.
McQueen told detectives her daughter, who was diagnosed as having bipolar disorder as a teenager, had been struggling more than usual with depression.
"She had been acting very irrationally and angry," McQueen told investigators, according to Newsday. "I tried to convince her to take a break from the kids and let me have them so she could recharge herself, but she always says she can handle it."
Campbell’s 4-year-old son was not with her when she was arrested. He was found safe with his father.
One of the last public posts on Campbell's Facebook profile, which appears to have been dormant since last summer, celebrated her daughters' first birthday in April 2018. Photos show the girls sucking on lollipops and wearing matching tutus, with purple flowers around their heads.
"In they first year, they have managed to stress me out to maximum capacity and still make me extremely happy," Campbell wrote. "Such a blessing and a headache it is to have twins. I love you girls till the death of me."
Police officials said Friday there had been no previous calls regarding Campbell and her children. Investigators learned the twins had not been in day care for the last few days of their lives.
A neighbor told the New York Daily News that Campbell had been struggling as a single mother and was facing eviction from the apartment in which she'd lived with her children for the past six months. Her landlord told the newspaper a court date in the eviction proceedings had been set for July 10.
That same neighbor, Aleshia Pike, told ABC7 in New York, however, that Campbell and her children appeared to be a typical family.
"The kids were happy, you didn't see any signs of neglect, nothing," Pike told the news station. "They always had smiles. She looked happy."
McQueen said her daughter, who worked as a home health aide, struggled with depression her entire life. According to police officials, she is being held on 24-hour suicide watch at the Suffolk County Jail.
"I tried so hard to help my daughter, Tenia," McQueen told investigators, according to the News. "I love her so much, but she has a mental disorder and there was just no talking to her today."