PHILADELPHIA—Prosecutors who earlier called on a social media site to remove posts that they say threatened a witness in a Philadelphia weapons case say some of the postings have been taken down.

But the district attorney's office said Monday that the Facebook site still has images calling for all "rats" to be killed "point blank period."

District Attorney Seth Williams said earlier in the day that the site had refused repeated requests to remove postings that he said included a witness statement about alleged purchases of weapons for drug dealers.

Officials said they believe someone other than Facebook removed the posts after the story was reported.

A Facebook spokesman said the company works with law enforcement to ensure the safety of users "and any assertion to the contrary is false."