Ledyard — Police since Thursday morning have been investigating an apparent hit list of Ledyard High School students someone posted on an Instagram account, according to Lt. Ken Creutz.

Creutz said when police learned of the hit list, which names a girl and a boy from each grade, they already had increased security at the school because of a rumored attack planned for Thursday, the 18th anniversary of the Columbine massacre.

After conducting a sanctioned interview with the student who allegedly was planning the attack and interviewing others who had pinpointed the student on Wednesday, police said they found no credible information there was going to be such an attack. They provided beefed up patrols at the school Thursday as a precaution, Creutz said.

Now police have launched a “full investigation” into the list.

Detectives, Creutz said, are at the school conducting interviews with students. IT personnel are working with Facebook, which owns Instagram, and Gmail to attempt to find out who created the account. The latter efforts may not yield anything because a person can create an Instagram account without verified, valid information, Creutz said.

The private account, which remains active, lists the students’ names in the area usually reserved for information about the user.

Creutz said police have updated several of the parents of the kids named on the list, and have been in regular contact with school personnel. The school’s principal, Creutz said, also took steps to alert all students and parents about what was going on.

“We would always err on the side of caution,” Creutz said. “Again, we’ve found nothing credible that anybody is in any danger, but we’re taking it seriously.”

l.boyle@theday.com