(CNN) -

Mexican authorities are still unraveling the horrors allegedly committed on nearly 500 children sheltered at "La Gran Familia" refuge in the southwestern state of Michoacan.

At The Big Family shelter, scores of children -- some as young as two months old -- were denied visits from their parents, virtually imprisoned in vermin-infested quarters and routinely subjected to physical, psychological and sexual abuse, authorities said.

Authorities raided the sprawling, squalid shelter in the city of Zamora Tuesday after a number of parents complained about being denied access to their children, Mexican Attorney General Jesus Murillo Karan told reporters.

"We found close to 500 children in truly deplorable conditions," Murillo said.

Victims told investigators that children were routinely forced to beg for money on the streets, eat unsanitary food and sleep on hard floors crawling with rats and roaches, Murillo said. It was not clear from Mexican authorities how so many children -- along with some adults -- came to be at the shelter.

The operator of the shelter, Rosa del Carmen Verduzco, was detained along with eight of her employees, authorities said. They were being questioned in connection with abuse and other charges.

"This is truly upsetting," Michoacan governor Salvador Jara Guerrero told reporters. "We did not expect to find such conditions... We must not allow these things to occur -- not in Michoacan, not in the republic."

Tomas Zeron de Lucio, chief investigator with the attorney general's office, said babies born at the shelter were allegedly registered under Verduzco's name. The biological parents were told that the babies would be allowed to leave when they came of age.

One victim told investigators that she asked Verduzco permission to leave the home when she turned 18 but was kept there as a worker for an additional 13 years, Zeron de Lucio said.

The victim said she gave birth to two daughters while living at the shelter and both were registered under another name, Zeron de Lucio said. She was allowed to see the girls for three hours every two months.

During her last meeting with Verduzco, the victim told investigators, she offered the shelter operator about 10,000 Mexican pesos -- or about $750 -- to get her daughters back.

"Get the money together," Verduzco reportedly told her, "and give me a call."

Authorities were working to rid the shelter of rats, bedbugs and roaches because there was no other place to immediately move the scores of children on short notice.

"Right now, we're undertaking an exhaustive cleaning because there were bedbugs, roaches and rats even in the food," Maria Ampudio, who works with a charitable organization, told CNN Wednesday. "The food given to the children was spoiled and outdated."

Ampudio said some girls reported being thrown to the ground and kicked in the head.

The shelter, which houses people ranging from newborns to 40 years of age, had been in operation for more than 40 years, authorities said.

The majority of the minors are between 3 and 17 years of age -- 278 are male and 174 female. There were 138 adults from 18 to 40 years of age also at the schedule. Also recovered were six babies and toddlers.

The website of "La Gran Familia" shelter said Verduzco started caring for abandoned children when she herself was a teenager. She later worked as a grade school teacher and earned a meager living to care for her charges. The children, the website said, helped raise money by selling newspapers and sweets in the town square.

Verduzco later left her charges in the care of a poor, elderly woman, according to the website. She moved to Mexico City to work with a charitable foundation, where she cared for 33 children and sent money back to Zamora. She later returned to Michoacan to start La Gran Familia, which housed more than 4,000 children over the years, according to the website.