The Iowa Department of Corrections says a large-scale investigation has turned up evidence of the synthetic drug K-2 at the prison in Clarinda.

Information from the Department of Corrections spokesman says staff at the Clarinda facility began noticing last week a sudden increase in the number of inmates experiencing symptoms consistent with those that have consumed a narcotic.

Prison leadership requested a large-scale search and dogs from six Iowa prisons searched for illegal narcotics and narcotic-laced materials. Approximately 60 inmates have been found to be involved in consumption, possession, or introduction of K-2.

The spokesman says the prison has known of an increase nationwide in substances coming into prisons through the mail. The evidence at Clarinda is being processed and the department says it will try to adjust the mail system for inmates to allow those in the prison to still receive mail, but in a safe and secure fashion.

The DOC says any decisions on charges against the prisoners will be made after the evidence is processed and the investigation is complete.

Radio Iowa