A Toronto area police officer has begun serving a more than seven-year jail sentence after Ontario's top court dismissed an appeal of his 2021 conviction on corruption charges earlier this week.

In a release issued Thursday, York Regional Police (YRP) said the Ontario Court of Appeal decision was handed down to former Const. Richard Senior, who served 16 years with the service, on Feb. 21.

Senior, who most recently worked with the District Community Response Unit in Markham, was arrested on Oct. 9, 2018, following a 10-month investigation by the service's Major Projects Unit.

That investigation led officers to believe Senior had been involved in "a number of criminal enterprises, including the attempted armed robbery of a quantity of cocaine; the theft and illegal possession of a York Regional Police shotgun; the trafficking of steroids to another officer; trafficking cocaine; and the disclosing of confidential police information," the release states.

During his trial in February 2021, the Crown alleged that the officer had filed an intelligence report about his former mistress and attributed the information to a fake confidential source. Other allegations presented by the prosecution included selling steroids to another undercover officer, stealing money he was given to pay informants and inappropriately accessing a police database to disclose confidential information.

Senior’s lawyer argued that his client’s actions were due to lack of experience and training. He also said that none of the incidents would have occurred without the “instigation” of police.

Ultimately, Senior was convicted of eight charges, including trafficking cocaine, trafficking testosterone, and possession of a weapon obtained by crime, possession of a weapon for a dangerous purpose, unauthorized use of a computer, and breach of trust and, later that year, sentenced to seven-and-a-half-years in jail.

“This unacceptable criminal behaviour is not tolerated by our organization and my thanks go to the members who investigated this case and the prosecutors who secured the convictions,” Chief Jim MacSween said in the Thursday release. “This is not a reflection of the hard-working, dedicated and professional members working each day to keep our community safe. We remain committed to being transparent and accountable to our community.”

Senior has been suspended without pay since 2020, when he was handed a custodial sentence. Under the Police Services Act, an officer cannot be suspended without pay unless they have been convicted of an offence and sentenced to a term of imprisonment.

Following the dismissal, Senior submitted his resignation from the service, the release states.