A man charged in connection with a fatal 2012 wrong-way crash that killed a man and his daughter claims "something" was slipped into his drink prior to the tragic incident.

Sabastian Prosa of Caledon, Ont., took the stand in his own defence on Wednesday. He is facing 12 charges, including impaired driving causing death, and has pleaded not guilty.

In the hours leading up to the crash, Prosa said he attended a music festival in Toronto's Downsview Park. After the event, he said he headed over to a friend's home where he said he had four drinks, before going to the Skybar at the Guvernment Entertainment Complex.

Prosa told the court on Wednesday that he intended to spend the night at his friend's home in Toronto and had even packed an overnight bag.

He said he did not intend to get behind the wheel the day of the crash, and claims he may have been drugged.

"I have reason to believe something was put in my drink," Prosa told the court.

Prosa was not asked who he believes may have drugged him, or where the alleged incident happened.

Police say that on Aug. 5, 2012, then-19-year-old Prosa was driving a GMC Envoy that was travelling in the wrong direction on the QEW eastbound to Highway 427 northbound. The SUV struck a Dodge Caravan at approximately 2:50 a.m.

The head-on collision claimed the life of 49-year-old Jayantha Wijeratne and his 16-year-old daughter, Eleesha. Wijeratne's wife, Antonette, was also in the minivan at the time of the crash and suffered serious injuries. The family was returning from a vacation in Florida.

Toxicology reports suggest Prosa's blood alcohol level was nearly twice the legal limit.

The trial is expected to resume on Thursday.

With a report from CTV Toronto's John Musselman