The mother of the victim is angry with the defendant, Aguilar, for preying on her daughter.
Aguilar, 44, is a husband, a father of three, including a daughter who's about the same age as the victim.
Aguilar was arrested for stalking and for child annoyance, involving a 13-year-old girl as she rode an Orange County Transportation Authority bus in Mission Viejo.
Authorities say the acts happened a few times a week, starting in September until earlier this month.
The girl's mother, who only wanted to be identified as "D," says her daughter told her that Aguilar would follow her on the bus and sit next to her. If she got up to move to another seat, he would get angry with her. He would also say inappropriate things to her. He gave her a rose one day.
The victim's mother began to think something was wrong when her daughter did not want to go to school anymore. Her daughter eventually told a friend, who then reported it to school officials.
Aguilar was arrested by undercover officers.
The girl's mother is angry with Aguilar that he took advantage of her child and wishes she would have said something sooner.
"I've taught her to respect adults and that's what she told me too. 'Mom, you've always told me to respect adults, but this one is making me feel uncomfortable,'" said "D." "So when you're teaching your kids to do the right thing and an adult takes advantage of that, that -- very angry."
"D" is grateful that Aguilar was caught before his actions may have escalated.
Aguilar pleaded guilty in a Santa Ana courtroom Tuesday. He was sentenced to 60 days in jail and three years probation.
Authorities are concerned that there may be other potential victim. If you have information related to the case, call Orange County Crime Stoppers at (855) 847-6227.