LA CROSSE, WI -

La Crosse County District Attorney Tim Gruenke says La Crosse police have identified a number of items that "appear to have been manipulated in some way since originally being packaged."

Gruenke made the statement in an email that went out on Thursday morning to a defense attorney.

The La Crosse Police Department’s evidence room is undergoing an audit, as a result of an incident with a La Crosse police officer “manipulating evidence inappropriately,” the email states.

“I use the word ‘manipulated’ because it may be the package was torn, or the tape holding the package appears to have changed from the time the original seal was made,” Gruenke continued.

Former La Crosse Police Lieutenant Brian Thomson faces two charges: attempted possession of narcotic drugs and misconduct in office. He was arrested on August 13. Charges are expected to be filed on October 2.

La Crosse police said they placed fictitious controlled substances under observation and Thomson removed those items. He was then arrested on the charges of attempted possession of a controlled substance and misconduct in office.

After an audit of the department’s evidence area, police say they have identified a number of evidentiary items that they think have been manipulated after the original packing of the evidence. Police have updated prosecutors regarding the items they believe were tampered with.

The Wisconsin Department of Justice Division of Criminal Investigation is conducting the criminal investigation. The La Crosse Police Department says it has “ensured the highest level of transparency throughout this entire proves.”

“The actions of Brian Thomson are not in any way an accurate reflection of the hardworking, dedicated, and ethical police officers in the La Crosse Police Department,” La Crosse Police Chief Ron Tischer said in a statement. “Brian Thomson shattered the trust of our agency and the community, and in doing so, must now face the consequences of his actions.”

The La Crosse Police Department is reviewing its evidence handling processes and its security procedures to ensure that all measures are taken to prevent this type of activity from occurring in the future. Interim corrective actions have already been taken.