24 Boston Schools Receive 'Disturbing' Letters

6/7 Update: Boston Police has released a list of 24 schools who received the suspicious letters Thursday.

Original post:

Boston Police plan to post extra security at city schools after several of them "received suspicious letters that contain some threatening and disturbing content," police and school officials said in a joint statement.

They did not say how the letters were threatening, but said there were no substances in them.

The letters were postmarked from Texas.

Authorities emphasized that the letters do not contain any credible threats.

-- Here's the joint statement from Boston Police and the Boston Public Schools:

Today, several different Boston Public Schools received suspicious letters that contain some threatening and disturbing content. Our schools have strong protocols in place to isolate suspicious letters and immediately notified the Boston Police. BPD is investigating the matter and has determined there are no substances contained in the letters. The letters, addressed to public schools in different areas of the city, all appear to be the same and are all postmarked from Texas.

Boston Police are collecting the letters and will investigate the source. We do not know of any credible threat to our schools. We are working with the JTTF and are processing the letters. School officials are isolating any letters with a Texas address and are contacting the police for pick up. To ensure families are aware, BPS has contacted all families through its automated phone message system.

Out of an abundance of caution, parents and students can expect to see an increased security presence in and around public schools. While we remain vigilant and are taking appropriate action, we reiterate there is no credible physical threat and the letters did not contain any substances. The safety of our students and school personnel is our top priority. We will update you on the investigation as information becomes available.

Thank you for your cooperation.