HALIFAX -- A senior police officer in Halifax has been accused of stealing an illicit substance that was seized during an earlier drug investigation, according to the independent watchdog that oversees police in Nova Scotia.

The Serious Incident Response Team confirmed Wednesday that 35-year-old Det.-Const. Laurence Gary Basso -- a drug investigator with 11 years of experience on the regional force -- has been charged with theft, breach of trust and obstruction of justice.

The agency says the allegations involve a substance known as "cut," which went missing from an police exhibit locker some time between Jan. 1, 2015 and March 14, 2015. The substance is used in the illegal drug trade to dilute drugs to increase quantity and profitability.

Ron MacDonald, director of the agency, said the substance in question is 700 grams of Lidocaine, a synthetic compound typically used as a local anesthetic.

MacDonald said the obstruction of justice charge relates to steps allegedly taken by Basso help someone else avoid arrest, but he said he could not offer further details.

"This type of behaviour, if proven, can have a significant impact on the justice system and ... Halifax Regional Police in particular," MacDonald said in an interview.

"Security of exhibits is a fundamental and important aspect of ... the investigation of offences and the justice system in general. These are significant allegations ... We were set up to handle these types of cases."

Halifax Regional Police have since conducted an audit of its drug exhibits, but it has yet to receive the results.

Police Supt. Jim Perrin said allegations of this type are rare.

"Any day a police officer is charged is a bad day in any community," he told reporters gathered at police headquarters.

"The public has expectations of their officers. Any time it's alleged that one of our officers has committed a significant offence ... it's concerning. That said, Const. Basso is entitled to due process. He hasn't been convicted of anything."

Perrin said there could be implications for cases Basso has handled.

"Any time an officer's credibility is questioned, there could be issues around that," he said. "There were some cases before the courts that the Crown made decisions on over the last number of months -- cases currently before the courts."

The superintendent declined to offer details, saying federal prosecutors were responsible for that part of the file.

When the independent agency started its investigation last May, Basso was suspended with pay and his status has not changed since then.

"We recognize that citizens expect police officers to be beyond reproach and that these charges will be as much a concern to you as they are to us," the agency said in a statement.

"We assure the public that this is an isolated incident which doesn't represent the hard work, dedication and professionalism our officers show day in and day out."

During its seven-month investigation, the team said it obtained statements from 20 police witnesses and five civilians.

Basso is scheduled to appear in Halifax provincial court March 30.