A mother is under heavy sedation and under guard in hospital after being arrested on suspicion of murdering her two daughters. The girls' father is a suspected mafia member who has been missing since 2006 after a mafia roundup in Ontario and Quebec.

Adele Sorella, 43, was arrested around 3 a.m. Wednesday after her SUV hit a pole on rang du Bas-St-Francois Street not far from her home. Investigators are trying to determine whether she lost control or hit the pole deliberately.

The bodies of the girls, Sabrina, 8, and Amanda, 9, were found inside the family home in Laval's Duvernay district by family members on Tuesday afternoon, who called 911 around 4 p.m.

The girls were pronounced dead on the scene and it's believed they had been dead for some time. The bodies had no obvious signs of violence, and police say there were no signs of violence on the home.

Police then launched a lengthy search for the mother, who had been reported missing and was described as "depressed."

Although she has been arrested, Sorella has not been formally charged. Police say she was not fit to speak with them, and is now in hospital under heavy sedation.

Inspectors plan on speaking with her sometime on Wednesday.

It is up to the crown prosecutor to decide whether to charge her formally, and if so, with which charges. Officials expect that will happen Thursday.

The girls

The girls' school, Genesis Elementary School, has made grief counseling available to students and parents.

Counselors will help parents identify signs of stress and grieving in their children that may mean they could use more counseling.

Father on the lam

The father of the dead girls is Giuseppe De Vito, who has been missing since 2006 following a big mafia roundup in Quebec and Ontario. De Vito is wanted on drug charges.

Series of cases

Tuesday's tragedy is just the latest in a series of murder-suicides and murder-attempted-suicides in Quebec that have been in the news this year:

March 26 -- Montrealer Louise Desnoyers reaches a plea deal in Vermont to the second-degree murder of her eight-year-old-son Nicolas on Lake Champlain in August 2006. Desnoyers, 51, had tried to kill herself. She'll spend at least 10 years in a U.S. prison.

March 25 -- The bodies of Sylvie Laneuville, 43, and her son, Jerome Laneuville-Grenier, 9, are found by police in their home in Sherbrooke. Police say they think it is a murder-suicide. She and her partner had recently split.

March 24 -- Jinane Ghannoum, 38, was shot dead by her husband in Laval, who then killed himself. Ghannoum had taken out three restraining orders against him - all of which he broke.

Feb. 21 -- A five-year-old boy and his three-year-old sister are found dead in a home in Piedmont, in the Laurentians. Their father, cardiologist Guy Turcotte, is charged with two counts of murder after he was sent to hospital for an apparent drug overdose.

Jan. 1 -- A suicide pact between unemployed real-estate agent Marc Laliberte and his wife, Cathy Gauthier-Lachance, ends with Laliberte being found dead along with their three young children in their home in Saguenay on New Year's Day. The mother has been charged with first-degree murder for her part in the pact.