A package containing "inappropriate wording" was delivered by mail this morning to West Philadelphia High School and police are trying to determine who sent it, according to authorities.
The package arrived about 8:40 a.m., a police spokeswoman said, though she could not elaborate on the message contained inside.
However, an internal police alert said that the package contained a news report related to the Newtown, Conn., massacre last Friday and a "racist letter saying you are next."
Agents with the local office of the Federal Bureau of Investigation have taken over the investigation, an FBI spokesman said this afternoon. No new details were available at 4 p.m. and the investigation is ongoing, the FBI spokesman said.
The school was not evacuated. The high school's principal was not available.