Under Pakistani law, opening a case does not mean that the person is charged with a crime but that police are investigating. However, people convicted of maligning the Prophet Muhammad can be sentenced to death.
According to Hayat, the boy told neighbors he forwarded the messages without reading them. Although authorities have released the boy's name, the Associated Press does not generally identify juveniles under 18 who are accused of crimes.
Pakistan's harsh blasphemy laws, sections of which carry the death penalty or life imprisonment, have drawn renewed international scrutiny this year after a young Christian girl in Islamabad was alleged to have desecrated the Muslim holy book, the Quran.
A Muslim cleric now stands accused of fabricating evidence against the girl, who has been freed on bail and whose mental capacity has been questioned.
Human rights activists say the blasphemy laws are too broad and vague, and are often used by people who are trying to settle scores with rivals or target religious minorities, who make up 5 percent of Pakistan's 180 million people.
Although many Muslims are accused of insulting Muhammad or other acts deemed blasphemous, minorities are disproportionately represented among the defendants, rights groups say.
However, the laws retain broad support in Pakistan, where Islamic conservatism is on the rise alongside extremism and many Muslims are highly sensitive about their faith.