Far-right talk-show host Alex Jones sent child pornography to the legal team representing family members of victims killed at Sandy Hook Elementary School school in a defamation case against him, the attorneys said.

The attorneys turned over what they said was child pornography to the Federal Bureau of Investigation when they received them in May, according to court papers filed Monday. They said the materials were included in a trove of discovery materials produced by Mr. Jones in the defamation case filed in Connecticut...