Complex sentence: On 5 June, the Al-Rahma Islamic Centre in Muswell Hill--which was used by children after school--was destroyed by a fire, and the building had been sprayed with graffiti making reference to the English Defence League.
Split into simpler sentences: On 5 June, the Al-Rahma Islamic Centre in Muswell Hill--which was used by children after school--was destroyed by a fire. The building had been sprayed with graffiti making reference to the English Defence League.