A West Ashley teen was arrested Tuesday after police said he posted “disturbing” messages online warning high-school students in Delaware not to show up at school.

Jason Thomas Fennell, 17, of Wayah Drive is charged with unlawful communication and third-degree computer crime, Charleston police spokesman Charles Francis said. He was booked into the Charleston County jail and his bail set at $1,562.

Charleston police and Delaware state police conducted a joint investigation after disturbing messages directed toward Concord High School in New Castle, Del., surfaced Oct. 5 on the social website Edmodo.

One of the posts read, “Don’t come to school Monday,” according to Francis. The message included an attached photo from Columbine High School, the Colorado school that was the site of a 1999 massacre.

Another post read, “Why build for something you’re already prepared for, Concord School Massacre 2013.”

Officials took the threats seriously and posted more police at the school, according to Delaware Online.

Investigators discovered that the posts were made in Charleston and traced them to Fennell’s computer, according to the incident report from Charleston police.

Fennell got access to the site by trying out websites used by students around the country and randomly trying passwords, Delaware State Police Sgt. Paul Shavack told Delaware Online.

Dave Munday contributed to this report. Reach Christina Elmore at 937-5908 or at Twitter.com/celmorePC.