Rotate object towards target without influencing AddForce

Hello, I want my zombie to walk towards my player. I already solved this. Now i want that the zombie not only walks toward my player, but also look at him.

First my moving script (I use a rigidbody):

 // Move
 
         // Calculate how fast we should be moving
         Vector3 targetVelocity = player.transform.position - this.transform.position;
         targetVelocity = Vector3.Normalize (targetVelocity);
         targetVelocity = transform.TransformDirection (targetVelocity);
         targetVelocity *= movementSpeed;
 
         // Apply a force that attempts to reach our target velocity
         Vector3 velocity = rigidbody.velocity;
         Vector3 velocityChange = targetVelocity - velocity;
 
         // Clamp velocityChange
         velocityChange.x = Mathf.Clamp (velocityChange.x, -maxVelocityChange, maxVelocityChange);
         velocityChange.z = Mathf.Clamp (velocityChange.z, -maxVelocityChange, maxVelocityChange);
         velocityChange.y = 0;
 
         // Rotate velocityChange to avoid
         velocityChange = Quaternion.AngleAxis (avoidInDegrees, Vector3.up) * velocityChange;
 
         rigidbody.AddForce (velocityChange, ForceMode.VelocityChange);
 
 
         // Apply gravity
         rigidbody.AddForce (new Vector3 (0, Physics.gravity.y * rigidbody.mass, 0));

I tried it with the following line and then my zombie looks at my player, but he walks toward him in a circle and not straight as it should be.

 // Look
         transform.LookAt (player.transform.position);

I know where the problem is, but i can not solve it. Thanks for your help!

EDIT: I found a solution: Just delete

 targetVelocity = transform.TransformDirection (targetVelocity);

and you will be fine if you are running the same issue as me. And add

  // Look
          transform.LookAt (player.transform.position);

and you will be fine.