  We call a subset $C$ of vertices of a graph $G$ a $(1,\leq \ell)$-identifying
code if for all subsets $X$ of vertices with size at most $\ell$, the sets
$\{c\in C |\exists u \in X, d(u,c)\leq 1\}$ are distinct. The concept of
identifying codes was introduced in 1998 by Karpovsky, Chakrabarty and Levitin.
Identifying codes have been studied in various grids. In particular, it has
been shown that there exists a $(1,\leq 2)$-identifying code in the king grid
with density 3/7 and that there are no such identifying codes with density
smaller than 5/12. Using a suitable frame and a discharging procedure, we
improve the lower bound by showing that any $(1,\leq 2)$-identifying code of
the king grid has density at least 47/111.
