Two Columbine High School students who scribbled a hit list in a park near the school have been suspended and may face expulsion, school officials said.

Authorities said students reported on Monday that the names of 11 students and two staff members were written in pencil on a pillar in Clement Park, with the words "My Hit List" above it. The two students, both juniors, confessed.

Authorities said the threat did not appear serious, but added that they are investigating fully anyway.

Saturday is the three-year anniversary of the nation's deadliest school shooting, in which Eric Harris and Dylan Klebold stormed Columbine High School, killing a teacher and 12 students before killing themselves.

"It's a shame that this had to happen so close to the anniversary," Jefferson County sheriff's spokesman Jim Shires said Thursday.

Jefferson County Schools spokesman Rick Kaufman said school officials have not found any other writings or materials related to the list. He said the two students may be expelled.

Columbine Principal Frank DeAngelis contacted the families of the people named in the list to ensure their safety.