What are the causes of obsessive thoughts about killing children, is it due to sihr (black magic), and how can one get rid of it?

"Obsessive thoughts may arise from neglecting the remembrance of Allah, or from envy, sorcery, or isolation. Symptoms of sorcery usually appear, such as: the bewitched person being prevented from approaching his spouse, or imagining things that did not happen, or forgetfulness, as occurred to the Prophet, peace and blessings be upon him. The symptoms may also be internal, such as dreams, but these do not indicate certainty of sorcery. To get rid of obsessive thoughts, persevere in the remembrance of Allah and contemplate His greatness, believe in divine decree and destiny, and be certain of Allah’s knowledge and wisdom."