The social worker seemed legitimate. Sheila — at least that’s what she called herself — was pitching assistance to financially struggling families of enlisted Marines. Her agency, she told potential takers, could arrange for diapers, formula, maybe $100 a month in benefits.

Sheila was quite specific, though, as she knocked on doors in the Oceanside apartment complex in the summer of 1980. She explained to the many people living in the off-base military housing that the aid was only for military families with an infant no more than a few months old.

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Within days, Sheila was gone. With her went Kevin Verville Jr., the 17-day-old baby of a Camp Pendleton corporal and his wife.

Kevin — whose 45th birthday is Saturday — remains missing, a rare unsolved case of an infant abduction by a stranger, one of about a dozen such cases still active across the country, according to Angeline Hartmann, spokesperson for the National Center for Missing & Exploited Children.

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Hartmann said authorities believe the fake social worker, who appeared to be pregnant, raised Kevin as her own child. “We strongly believe that Kevin Jr. is still out there alive and may not know his real identity,” Hartmann said.

On Tuesday, the organization known as NCMEC released an age-progression image of Kevin Jr., an image Hartmann said was created by a forensic artist at the organization using family photos.

“This is a likeness. This is not what we’re saying Kevin Verville Jr. looks like today,” she said. Rather, the intent is to spark recognition. There is also a blog about the case.

Angelica Ramsey, 40, is Kevin’s younger sister, and her push for information a few years ago has reinvigorated the case. On Tuesday, she pleaded for help finding a brother she has never met. Ramsey said her family has entered their DNA in commercial databases, including Ancestry and 23 and Me. The FBI says the agency is also on the lookout for DNA matches.

The Colorado resident and her father, who lives in Montana, both attended a news conference in Oceanside in hopes of reigniting the case. Ramsey said her mother, Angelina Verville, has suffered two strokes in recent years and is no longer verbal. The couple divorced long ago. Their daughter said the pain of the abduction remains sharp.

According to authorities and news reports, the woman posing as a social worker had knocked on many doors at the 640-unit complex on Bougainvillea Street over the course of several days, pitching her offer to new parents. The Verville couple had talked it over and agreed to sign up for help. Kevin Verville, then 21, was a corporal. Angelina, then 22, was a new immigrant to the U.S. from the Philippines. This was their first child.

“I think the key is that she kept knocking on doors until she found the baby that she was looking for,” Hartmann said.

Authorities released these sketches of a woman who called herself Sheila and who abducted a 17-day-old baby from an Oceanside couple in July 1980. (National Center for Missing and Exploited Children) 

On July 1, 1980, Sheila returned to the doorstep of their upstairs apartment as they returned home from the commissary. Kevin Verville agreed to put away groceries while Sheila drove his wife and baby to the agency office to fill out paperwork.

Sheila drove mother and child down state Route 76 east across Interstate 15. They talked about the baby, who had been hospitalized for jaundice but was recovering. “He is a good baby,” Angelina had told Sheila.

Sheila stopped at a house in an orange grove and explained she was there to pick up another mom. But Sheila said she wasn’t feeling well and asked Angelina if perhaps she could get out and knock on the door.

Angelina told the San Diego Evening Tribune newspaper she handed over the infant, got out and headed to the home. “(Sheila) was holding my baby, tickling him under the chin, and they were both smiling,” she said.

Sheila drove off.

Angelina ran after the car, which authorities said at the time may have been a 1975 Mercury Cougar sedan.

The FBI was soon involved, the San Diego Union newspaper reported at the time. Agents immediately developed a psychological profile: Sheila may have lost a male baby within recent weeks, possibly shortly before or after birth. She may have been simulating a pregnancy. She probably was living alone.

Three years later, the Evening Tribune reported that the stumped FBI agent in charge in San Diego said he believed the kidnapper wanted a “replacement baby” and was raising Kevin Jr. as her own child.

Sheila was described as White, about 5 feet, 2 inches tall, roughly 20 years old, with curly red hair and bearing a tattoo of an X or cross in a circle in the webbing of her left hand. She spoke some Tagalog, Angelina Verville’s native language.

“We need your help to find answers,” Hartmann said. “Kevin deserves answers.”

The FBI is honoring a $10,000 reward for information that leads to locating Kevin Jr. and the arrest of those responsible. Tips can be submitted at 1-800-CALL-FBI or tips.fbi.gov.