If the position vectors of the points A, B, C and D are
\( \mathbf{A} = 3\hat{i} + 2\hat{j} - 3\hat{k}, \)
\( \mathbf{B} = \hat{i} + \hat{j} + \hat{k}, \)
\( \mathbf{C} = 2\hat{i} + 5\hat{j}, \)
and
\( \mathbf{D} = \hat{i} - 6\hat{j} - \hat{k}, \)
respectively. Prove that the points are collinear.