A grandmother from Wallaceburg, Ont., has been sentenced to life in prison for drowning her grandchildren two years ago.

Jane LaMarsh, 50, drove her car into the frigid St. Clair River, taking the lives of Tyler Bernard, 10, and Taiya Talbot, six, who were trapped in the vehicle as it sank.

LaMarsh's own 12-year-old daughter was also in the car but escaped and managed to swim to shore.

The grandmother pleaded guilty before Justice Renee Pomerance in Sarnia to two counts of second-degree murder and was sentenced to life in prison with no chance of parole for 10 years.

LaMarsh was driving on the St. Clair Parkway on Dec. 3, 2009, with her daughter and two grandchildren, court was told. She made a U-turn and drove down an embankment and into the 9 C waters of the St. Clair River.

Sarnia police said an examination of the vehicle found nothing mechanically wrong. It sank in the St. Clair River on Dec. 3 with two small children inside. Sarnia Police ServiceEmergency responders were unable to revive the children after pulling their bodies to shore about 90 minutes later.

In a victim impact statement, the children's mother, Stephanie Bernard, told court she feels the pain of loss every day.

Sarnia police Det. Sgt. Scott MacLean said Bernard had wanted to believe her children died as the result of an unfortunate traffic accident.

"This guilty plea has brought it back that … 'how could my mother ever do this to me and to our children?'" MacLean said.

Court heard LaMarsh had been passively suicidal and took steps to seek psychiatric help.

LaMarsh "didn't receive the medical help she so desperately needed," Pomerance said. The judge recommended the sentence be served in a facility that offers psychiatric assessment and treatment.

With files from The Canadian Press