Police are asking for the public?s help to catch a man who threatened a mother and her child in Hempstead before sexually assaulting her.

Authorities say the young mother was finished shopping on Greenwich Street when she strapped her 2-year-old daughter in a car seat Friday. The woman had just put her packages away in the trunk when police say she found a man in the passenger seat pointing a gun at her. Officials say the suspect turned the gun on the child and made the woman drive to a parking lot where she was forced to perform sex acts on him.Police say the situation could happen anytime, especially during the holidays when people are more preoccupied with shopping bags than their surroundings. Officials urge people to shop with a friend, park under a light, have car keys ready and look in their cars before getting in. Anyone with information about the assault is asked to call Crime Stoppers at 1-800-244-TIPS.