Complex sentence: She developed a mental illness and ran off with the baby and was found the same day but then also played a series of bizarre pranks, such as defecating in a box and posting it to next door neighbours, the Ashworths.
Split into simpler sentences: She developed a mental illness and ran off with the baby. She was found the same day but then also played a series of bizarre pranks, such as defecating in a box and posting it to next door neighbours, the Ashworths.