A 12-year-old girl was asked to get into a car in Worthing on 20 June
The girl said a silver Skoda stopped in Ashacre Lane, Salvington, and a rear passenger got out and asked her to get in the car.
The girl ran away and called the police.
Detective Inspector Andy Bennett said: “The girl was shaken but otherwise unharmed. She is with her family and talking to us about what she saw.
“She describes the man, who was with two other men in the car, as white, skinny and scruffy, aged about 20 and with dark short hair and stubble.
“This is a very busy road especially at 5pm when she said this happened. We are looking into the circumstances and at this time are keen to find anyone who witnessed the incident.
“If anyone saw a silver car, she describes as a Skoda, stop and someone talk to young girl before rejoining the traffic we would like them to contact police by calling 101 and quoting serial 1183 of 20/6.”