After Oregon child welfare workers overlooked allegations that an infant suffered traumatic injuries at his small day care center, a second baby boy died months later in the care of the same day care operator, according to a lawsuit filed this week by the boy's estate.

The dead boy's pediatrician also failed to report physical signs of abuse that she noted prior to his death, the suit says.

Allan "A.J." Swearengin's parents were never told about the initial reports of abuse at the Lane County day care, the wrongful death lawsuit contends. A.J. suffered repeated injuries at the day care before he was found unconscious there Sept. 12, 2016.

Doctors pronounced him dead 90 minutes later. He was 10 months and six days old.

The $18.75 million lawsuit contends the Department of Human Services and his pediatrician at a Eugene clinic failed to protect him and prevent him from dying. Had child welfare workers investigated the role the day care worker may have played in the first baby's traumatic brain injuries, as that baby's parents urged, they could have prevented A.J.'s death, the lawsuit says.

Another doctor who reviewed A.J.'s medical records after his death concluded he died of non-accidental injuries that were "highly similar" to the first baby's, the lawsuit says. My Little Buttercup Day Care was the "only commonality," the suit says.

Instead of investigating if the caregiver caused the first infant's injuries, case workers faulted that baby's parents, the lawsuit says. The parents insisted their son was hurt at day care, not at home.

"Whatever else in terms of obligations, if DHS had done an investigation and spoken with the babysitter and actually looked at these files, A.J. would be alive today," said Portland attorney C.J. Graves, one of four attorneys representing the boy's estate.

"It's basic -- just a warning that parents should be concerned, because how else is a parent going to know this?"

A litany of recent lawsuits have accused Oregon's child protection agency of grave failures that have led to deaths or severe abuse of children. One suit filed earlier this month claims two young sisters were sexually abused in foster care by a 13-year-old with known behavioral issues.

Christine Stone, a spokeswoman for the Department of Human Services, said the agency does not comment on pending cases and declined to comment on A.J.'s suit.

The lawsuit says A.J.'s parents had no inkling of the prior abuse complaints in the other baby's case until case workers looked into the circumstances of A.J.'s death months later as part of a wider review.

The day care worker had informed them by text of several injuries their son sustained in her care, but she said they were caused by him falling and hitting his head and face or, in one instance, by her falling while carrying their son. In multiple instances, starting when he was four months old and continuing until shortly before his death, he bled or was bruised at My Little Buttercup, the suit says.

A.J.'s estate alleges that Dr. Whitney Benz should have alerted officials to his injuries. Oregon law requires doctors to report any signs of suspected child abuse.

After A.J.'s death and without notifying A.J.'s parents, Eugene Pediatric Associates reviewed his records and determined two injuries Benz documented during the boy's short life may have indicated abuse, the lawsuit said.

Benz is no longer listed among the doctors on staff at Eugene Pediatric Associates. A message left for the clinic's owner Wednesday was not returned. A working number for Benz could not be found.

The Oregonian/OregonLive is not naming the babysitter because no criminal charges have been filed, and she is not named as a defendant in the lawsuit. She did not return a message left with her husband Wednesday.

The woman advertised "small, quiet private in home care" on websites such as Sitter.com, saying she cared for children ranging in age from six weeks to 12 years old. She wrote that she was certified in CPR for children and first aid for babies.

She was unlicensed because no license was required. Oregon law allows people to care for three children without a license, among other exemptions.

Deaths at licensed day care providers are relatively rare, and regulators have reported one so far this year. But the state doesn't regulate unlicensed providers, so it's impossible to know how many children have died at places such as My Little Buttercup.

The lawsuit said the babysitter operated the day care with her husband in her mother's home. The exact location is unclear. She advertised it to families in Eugene.

A.J.'s parents started taking him there five days a week in January 2016, the lawsuit said.

The next month, another infant in the woman's care, identified only as B.L., started vomiting, became lethargic and had trouble feeding. He was ultimately flown to OHSU Hospital in Portland and diagnosed with head injuries, including internal bleeding on both sides of his head.

"The injuries were noted as highly suspicious for nonaccidental trauma or significant accidental trauma," the lawsuit said.

Doctors alerted DHS to the suspected abuse, the lawsuit says. Child protection workers focused on his parents and placed B.L. in foster care, according to the suit.

When A.J.'s parents asked what had happened to B.L., whose parents they did not know, the day care worker said the baby had been injured and the boy's parents were at fault, according to the suit. Concerned, A.J.'s mother, Caroline Swearengin, asked Eugene police, who told her DHS suspected the parents, not the day care.

A.J.'s first documented injury came the next month, the lawsuit says.

The day care worker told Caroline Swearengin in March 2016 that she fell as she was holding 4-month-old A.J. That May, she twice said that 6-month-old A.J. had "faceplanted" and bruised and bloodied his face.

His parents took the boy to receive medical care several times that spring and summer. Dr. Benz noted his injuries, but not concerns related to them, the lawsuit says. After his caregiver told his parents she fell on him, Benz wrote that he "was dropped accidently by his day care provider and has a resolving bruise on his buttocks. No other injury or bruising," according to the lawsuit.

State records show Benz obtained her Oregon medical license in 2015 and has not been the subject of any disciplinary actions or malpractice lawsuits. It's not clear where, or if, she practices now.

Benz saw A.J. in July 2016 after he started "vomiting profusely" after his parents picked him up from day care, the lawsuit says. The doctor saw him again August 9, according to the timeline spelled out in the lawsuit. A.J. had slipped at home three days earlier, and his parents noticed a bump on his collarbone. X-rays showed the 9-month old had broken his clavicle 10 to 14 days earlier, and possibly again when he slipped at home.

"Dr. Benz did not report A.J.'s injuries, including his twice-fractured collarbone, to DHS or law enforcement or any other potentially responsive agencies," the lawsuit says. Other doctors who looked at the X-rays after his death said the initial break could only have been caused by a "grab and shake" or by compression of the collarbone, not by slipping and falling, the suit says.

The doctor saw A.J. for a final time August 19, after the day care operator told his mom he had fallen again and bruised his lip. Benz noted what happened in medical charts and that his earlier injuries seemed to be healing.

Less than a month later, A.J.'s parents dropped him off at day care for the last time. By early afternoon, he was dead.

A.J.'s parents were not told that doctors had believed the broken collar bone indicated abuse or informed about the extent of his injuries until several months later, the lawsuit contends. His cause of death was ruled as undetermined.

They did not learn child protection officials had questions about his death until March 2017, according to the lawsuit. The next month, case workers told them they were probing the link between A.J.'s injuries and the injuries suffered the other boy at the day care.

The state ultimately reversed its findings against that baby's parents, the lawsuit says, "noting that B.L. was in (the day care worker's) care immediately prior to his hospitalization, and further acknowledging that DHS did not assess (the worker) in the course of the investigation into B.L.'s injuries."

The state notified A.J.'s parents this April that they had "reasonable cause to believe the day care provider physically abused" A.J. The letter indicated the other baby "became symptomatic for shaken baby syndrome" while in the day care worker's care.

Although DHS found reasonable cause to believe that the day care worker caused the injuries, it's unclear whether police consider it a criminal or potentially criminal case, and the county prosecutor has not opened an investigation.

Assistant District Attorney Bob Lane said he knows about and was consulted on the cases of both infants who attended My Little Buttercup. Prosecutors did not take steps toward filing charges as a result of those consultations, he said. The office could change course later, he said.

The day care operator previously ran a different day care. State records show she was licensed to run that day care from 2002 to 2010. Regulators cited the day care for four violations in 2009, according to Office of Child Care data provided to The Oregonian/OregonLive..

She and her family now operate a horse stable, a horticulture business and a barbecue business, state records show.

-- Molly Young

myoung@oregonian.com