A targeted push

(My daughter is writing this for me): I was waiting to cross the street. A young man (maybe early 20s) walked to pass in front and very close to me and then disappeared. Then I didn't know but a couple minutes later, he went behind me. He pushed me (on my left shoulder). Not hard enough to make me fall. He then ran across the street and looked back at me. He did not say anything. A young woman was near me and saw it happen and came over and she shook her head and said sorry and checked on me. I said thank you. She stayed a minute and the light turned green and we cross the street.