name-removed, Dec-20 09:39 am (PST):
Thank you for the report.
We do not tolerate child pornography on Twitter. When we are made aware of such images they will be removed from the site without further notice.
For accounts that have not posted such images, if they are determined to fall within these guidelines (http://www.missingkids.com/
en_US&PageId=2447 ), we do report them to the National Coalition for Missing and Exploited Children (NCMEC); law enforcement is then able to review those reports and determine which they believe merit further investigation.
As we are not law enforcement, we cannot engage in offline investigations of violations of the law. However, we do notify law enforcement agencies who can. As such, it's important to remember that simply removing accounts and/or Tweets does not result in the underlying possible criminal act being identified and prosecuted and can instead lead to the removal of evidence that law enforcement may need to determine whether or not charges should be brought and/or an investigation begun.
You are also welcome to file an additional complaint with NCMEC to provide them with context or more information; you'll find the link here: https://secure.missingkids.
Twitter Trust & Safety