Updated

The first newborn was discovered swaddled in a blanket on a park bench, an umbilical cord still hanging from his tiny body. Then, at neat 11-month intervals, two more abandoned babies were found in parked pickup trucks in the same neighborhood.

This week, DNA tests established all three babies were almost certainly born to the same mother.

Now, in a heartbreaking mystery that has transfixed this central California farm community of 7,300, investigators are trying to find the mother and figure out what drove her to such desperate lengths.

"How can the relatives not see this girl pregnant, and then see that she's not pregnant anymore and not ask where's the baby? Somebody must know something," said Hortencia Espino, 81.

All three newborns were found within a two-block radius. The first two — a boy and a girl — survived and are now wards of the state.

The third baby was found dead of exposure on the cold night of Dec. 3. She was enveloped in a sweatshirt in the bed of a pickup parked near the high school, some 60 miles southeast of Fresno. The coroner concluded she was alive for less than a day.

On Wednesday, community members held a funeral Mass for the baby girl, who was dubbed "Angelita DeOrosi," or Orosi's little angel.

"This community was very upset and confused after the first baby, let alone the second and the third, who passed away," said sheriff's Sgt. Chris Douglass. "Having the memorial will help bring them some closure and give the babies the love and respect and dignity they should have received in life."

Orosi, a town encircled by fig and lemon orchards, has long been the kind of place where everyone seemed to know each other. But that is changing, with new housing developments going up and a burgeoning gang problem that has led to a rise in violent crime.

As upset residents built makeshift shrines in memory of Angelita, authorities interviewed local women they thought might be involved. But DNA testing eliminated them as the babies' mother.

After exhausting all leads, officials are asking the community for help finding the parents and are offering a $5,000 reward. Police said the mother could face criminal charges. But they also said they want to make sure she doesn't do it again and isn't in some kind of distress.

Investigators would not speculate as to the reasons for the abandonment, such as whether the mother might have been a prostitute or a rape victim.

"Whether the mother is in a physical state of danger or a mental state where she feels she can't ask for help, our heart goes out to her," Karen Franzen, manager of Dopkins Funeral Chapel in Dinuba, which donated a casket and cemetery plot for Angelita.

The first deserted newborn was found on Feb. 10, 2005, a barely breathing boy with a body temperature of just 85 degrees. On January 8, 2006, a resident discovered a full-term baby girl inside a pickup two blocks away, clothed in an undershirt and pants.

On Monday, sheriff's officials announced the DNA results. The first two babies probably had the same father, but Angelita was fathered by a different man.

California and 46 other states allow parents to legally abandon a child at a hospital or other designated safe zones within 72 hours of birth, no questions asked.

Since California's law went into effect in 2001, parents have safely surrendered 182 babies at fire stations, emergency rooms and other safe havens, according to state officials.

"This little community is a family. We know pretty much everyone else's business and they know ours," said Eugene Etheridge, principal of Orosi High School. "It's concerning that this could happen again when the most precious thing we have is our children."