OROSI, Calif. - 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 neighborhood.

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

Now, in a sad mystery that has transfixed this central-California farm community of 7,300, investigators are trying to find the mother and learn what drove her to allegedly abandon the children.

"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 wards of the state.

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

Yesterday, a Catholic church held a baptism and funeral Mass in Spanish and English for the girl, who was dubbed "Angelita DeOrosi," or Orosi's little angel.

Later, under the shade of a corrugated plastic awning, sheriff's officials and grandmothers delicately sifted handfuls of dirt onto her white coffin before it was lowered into the earth.

Marely Pena, who found the infant in her father's truck, cried behind dark glasses.

"I ask myself every day what if she had been alive. We could have saved her," said Pena, 25. "I just hope the mother comes forward to please just make us feel at ease."

Encircled by fig and lemon orchards, Orosi 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 gang problem that has led to a rise in violent crime.

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

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 distress.

"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," said 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 Jan. 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.

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