Mate in 4. Simple.
Sort:
2. ... Ra1 is unnecessary. 2. ... Qe3+ will make this a mate in 3.
a) 3. Re2 Qxe2#
b) 3. Kd1 Ra1#
And 2. Rf4 from white will prevent the immediate mate. Though it does lose even more material for white and mate can't be far off.