Jesus Ramirez allegedly abused the girls between 2011 and 2012 when he lived in South El Monte.
He was arrested April 26 and remains in custody.
Ramirez has been charged with three felony counts of lewd acts with a child and is being held on a $1.3 million bond.
The Los Angeles County Sheriff's Department said based on the nature of the allegations and Ramirez's access to children, detectives believe there may be additional unidentified victims and are seeking the public's help.
Anyone with information is urged to contact L.A. County Sheriff's Department's Special Victims Bureau at 877-710-5273.
If you prefer to send a tip anonymously, you can call Crime Stoppers at 800-222-TIPS (8477), or download the "P3 Tips" mobile app.
You can also submit a tip online on the Crime Stoppers website.