LAKEWOOD, Colo. -- The cause of death of a senior at Brady Exploration School in Jefferson County may never be determined, the county health department said Tuesday.

Earlier, Jeffco Schools spokeswoman Lynn Setzer said the death was not due to bacterial meningitis, but later clarified the statement to say the district may have been misinformed. Setzer said meningitis remains a possible culprit.

The Jefferson County Health Department had been asked to look into the death of the 12th-grader and said Tuesday that it received inconclusive test results from the autopsy.

"This is not an unexpected finding when working with samples taken after death. Therefore, we will be unable to definitively define the cause of death," the health department said in a statement.

The school said it was notified of the death last Thursday, and sent letters out to parents on Friday. The student who died was not identified.

Bacterial meningitis is a serious infection of the fluid in the spinal cord and the fluid that surrounds the brain.

Brady Exploration is located in Lakewood and is an option school. The school offers classes from kindergarten through 12th grade.