A B.C. court heard dramatic testimony Tuesday about an undercover police operation into Carol Berner's involvement in the death of four-year-old Alexa Middelaer.

On May 17, 2008, Alexa and her aunt had just arrived to feed a horse on a quiet Delta road when a car crashed into them from behind, killing the little girl.

Berner is now on trial at Surrey provincial court for drunk driving in connection with that crash.

The court heard that in 2008, police conducted an undercover investigation nicknamed "Operation Angel," in which an officer befriended Berner over drinks, a Madonna concert and a trip to Vancouver Island.

It was on that trip, six months after the crash, that Berner told the officer a little girl had died in what she described as an accident.

Berner was later secretly taped, admitting to an officer in a hotel room that she drank at least three glasses of wine, and may have been driving too fast on the day of the accident.

She told the officer she had an anxiety attack when she lost control of the car, and may have hit the gas, rather than the brake.

But defence lawyer David Tarnow said that evidence doesn't necessarily indicate Berner was driving dangerously.

"She spoke about going slightly over the speed limit, but to be dangerous, you certainly have to be more than slightly speeding," Tarnow told reporters outside the courtroom.

Alexa's mother Laurel Middelaer said that she was troubled watching the undercover tape in court.

"That was really tough to watch -- especially how cavalier (Berner) is in talking about it, and it's just amazing to me how somebody can repeat lies over and over to themselves, and it actually becomes the truth," Middelaer told reporters.

The trial continues on Wednesday.

With a report from CTV British Columbia's Leah Hendry