Glendale police arrested 19-year-old Jordan Liu of Alhambra last Tuesday on charges of sexual assault with two children under the ages of 10.
Police allege that Liu had been molesting the children over an 8-month period. They also say that he had a clean record.
"I liken it to, well there's not going to be a record until you get caught," said Sgt. Tom Lorenz from Glendale Police.
The mother said she was reading an article about the Penn State sexual abuse scandal to her 8-year-old son to provide awareness and education about the topic, when she found out that he and his 3-year-old brother were allegedly molested by their babysitter.
"She started to describe some of the acts that are not good," said Lorenz. "Unfortunately during this conversation the child began to cry and the mother learned then that their current babysitter was doing similar acts."
Authorities said the family hired Liu through the babysitter service website, Sittercity.com. Liu was also using Care.com to advertise his child care services.
Sittercity.com released a statement, saying, "Sittercity takes safety very seriously. Each caregiver who registers on Sittercity is pre-screened to verify his/her identity and the caregiver's information is checked against state sex offender registries. In addition, we allow members to run background checks on the site through LexusNexus background checks."
Care.com also features similar requirements including background checks, references and reviews. They also released a statement saying, "In the case of Jordan Lio, Care.com has run eight verification checks and one background check since 2009. These checks came back clear for this provider."
Liu pled not guilty to the charges and is being held on $2.7 million bail. His next court appearance is scheduled for Jan. 5.
The Glendale Police Department said it doesn't know if there are other victims, but Liu may have spoken to more than 100 parents through the websites. It's unclear how many of them hired him as a babysitter.
Anyone with information is asked to contact Glendale Crime Stoppers at (800) 222-TIPS.