Four-year-old Jessica Cortez was home safe and happy Wednesday morning, three days after the little girl disappeared from a Los Angeles city park.

Jessica's parents "went from hell to heaven in thirty seconds" when they learned their daughter was safe, LAPD chaplain Father David Bowser said on television Wednesday morning.

Patricia Cornejo, 34 who brought Jessica dirty and barefoot into a medical clinic Tuesday afternoon after Jessica complained of a sore throat, was arrested on suspicion of kidnapping.

"We have gathered some evidence, and we're certain she is the prime suspect in all of this," interim Los Angeles Police Chief Martin Pomeroy said Wednesday. "We need to collect a few facts and take it to the district attorney and have charges filed."

Pomeroy said Wednesday that Cornejo, a mother of two girls and two boys, has had no major run-ins with police and has no record with child-services authorities.

Jessica apparently spent the entire time of her disappearance in the woman's home and was not physically harmed in any way, Pomeroy said.

"I don't believe there was great force used and perhaps nothing more complicated than this woman held hands with Jessica and walked her out of the park. ... She's a very friendly and outgoing girl and perhaps that's the reason why she went with this woman," Pomeroy said.

Cornejo's girls, ages 4 and 10, were placed in protective custody. The boys, ages 14 and 8, live separately with their father, Pomeroy said.

"The motive remains a bit hazy right now," Pomeroy said. "We're not sure why this woman did what she did."

Found shortly after 5 p.m. at St. John's Well Child Center, Jessica was immediately taken to Childrens Hospital, according to Officer Jack Richter.

Mother and daughter held a joyful reunion.

"The mother, as you might expect, was weeping hysterically, and little Jessica threw her arms around her mother and began to laugh hysterically. And then after a few minutes, she also began to weep," Pomeroy said.

"We think it will be a long time before they let go of one another," he added.

Jim Mangia, executive director of the clinic, said Jessica was brought in at about 5 p.m. Tuesday by a well-dressed woman in sunglasses who refused to sign the clinic's forms and wrote that the child's name was Maria Ortiz.

The clinic's receptionist immediately recognized Jessica, who was wearing shorts and no shoes. She was very dirty and her hair had been cut short, Mangia said.

When the woman went to the bathroom, clinic staff questioned Jessica.

"We went in and spoke to Jessica, asked her name, she said it was Jessica -- the woman had signed in a different name -- and then we asked her if that woman was her mom and she said no ... all the time we were waiting for the police," Mangia said.

"We assumed that she was a kidnapper given how she was acting," he added.

St. John's Well Child Center, in a beige, nondescript building near the University of Southern California, is about five miles away from Echo Park and provides free medical care to children.

Jessica was examined at two local hospitals, then sent home with her parents. Police and a hospital official said she was unhurt.

"She appears to be in good condition," said Childrens Hospital spokesman Steve Rutledge.

Pomeroy said Jessica appeared in good spirits, although she expressed some concern that her hair had been cut. He said detectives assured her she still looked fine.

A statewide "Amber Alert" was activated on Sunday night immediately when she was reported missing, but rescinded after Jessica's 5-year-old brother told police he thought he saw Jessica's dress in the water of Echo Park's lake.

Hope that she was still alive was resparked Monday, after divers found nothing in the lake and witnesses came forward saying they had seen her walking with a man in the park hours after her parents last saw her. The Amber Alert was reactivated.

The Amber Alert, distributing information to law enforcement agencies, news media and motorists through traffic signs, was reactivated.

Police were still looking for that man and trying to figure out his connection to the woman, but he was no longer considered a suspect, Pomeroy said in a Wednesday morning press conference, adding that police now thought that the woman had taken Jessica from the park.

The Amber Alert system, which distributes information to law enforcement agencies, news media and motorists through traffic signs, was adopted in California after the slaying of 5-year-old Samantha Runnion, and was credited with assisting the recent rescue of two teenage girls.

The alerts are named for a 9-year-old Texas girl kidnapped in 1996 and later found dead.

Rafael Cortez, the girl's father, and Maria Hernandez, her mother, sell tacos from a small stand across the street from the park. Witnesses said they often let their three children -- Jessica, a 5-year-old brother, and a younger sister -- play unattended in the park.

Another daughter recently died in what police Lt. Jose Perez described only as "an accident with a Venetian blind."

Cheers rang out through Echo Park Tuesday afternoon when Mayor James Hahn announced, "Little Jessica's been found!" Bells sounded at a nearby church and people in the park cried and embraced.

"Viva Mexico, viva La Raza, viva los Americanos!", said Victoria Robles, 66, who sells corn at the park and knows Jessica's family.

Maria Ramirez wrapped her arms around her 7-year-old granddaughter.

"I didn't know her but I have goose bumps," Ramirez said. "I'm just so happy."

The Associated Press contributed to this report.