Halton Regional Police say a 16-year veteran of the force has been arrested and charged with breach of trust and theft after approximately 30 drug exhibits were allegedly tampered with over a three-year period.

In a news release issued Sunday, Halton police say a “comprehensive internal audit” of all drug exhibits was launched in the fall of 2016 when a drug exhibit "anomaly" was discovered by members of the drug and morality unit.

“The audit revealed that approximately 30 exhibits had been tampered with. In all instances, the exhibits involved prescription or illicit opioids, the most common example of which is OxyContin,” the news release read.

“As a result of this information, Chief of Police Stephen Tanner contacted the Toronto Police Service in November, 2016 and requested they undertake an independent, external criminal investigation relating to the exhibits.”

The Toronto Police Service began their criminal investigation into the matter in December 2016 and their probe resulted in the arrest of Halton Regional Police Staff Sgt. Brad Murray.

Halton police say Murray was a member and supervisor of the drug and morality unit from January 2013 to May 2016 and it is during that time that police allege the criminal offences occurred.

Murray is facing two counts of breach of trust, two counts of theft under $5,000 and obstructing justice.

He has been suspended from duty with pay, a stipulation outlined in the Police Services Act of Ontario.

Halton police say in addition to the charges, Murray will also face disciplinary procedures in accordance with the Police Services Act.

“As a result of the investigation, and confirmation that exhibits had been tampered with, a number of drug related trials have been stayed by the Prosecution," the news release continued. "The full ramifications of this situation as it relates to court prosecutions and potential withdrawal of charges will not be known for some time.”

Chief Tanner said the alleged incident “violates public trust” in the work police officers do.

“We are committed to dealing with this issue transparently and thoroughly, guided by our longstanding principles of Excellence, Integrity, Justice, Trust and Respect, Teamwork and Accountability. We will continue to cooperate fully with, and support the decisions of, the Toronto Police Service, Public Prosecution Services of Canada and the Ministry of the Attorney General's Office,” Tanner’s statement read.

“In light of the findings and going forward, the Drug and Morality Unit has implemented additional measures to preserve the integrity of all seized drug exhibits. I am confident in the security of our Service's drug exhibits and that no other cases or types of drugs are in question."

Murray's first court appearance has been set for June 27, 2017 at the Milton Provincial Courthouse.