I work on complex numbers. Let $Q \subset \mathbb P^4$ be a quartic threefold that contains a double line $l$. I want to compute the normal sheaf of $l$ in $Q$, and I seem to find only two possible cases,

$$\mathcal O_l(-1) \oplus \mathcal O_l\quad\text{and}\quad\mathcal O_l(-2)\oplus \mathcal O_l(1).$$

Can someone tell me which is the right one? There should be some paper by Iskovskikh about that but I am not able to find a copy of that.