grope at (someone or something)
To try, often unsuccessfully, to touch, catch, or grasp someone or something. I groped at Sally's hand as the car came careening down the street. Tanya groped at the string, but it slipped away, and the balloon floated toward the sky.
grope at someone or something
to reach for someone or something blindly. She groped feebly at the form she could hardly see. Sharon groped at Frank as he ran out to get the doctor.