Three teenagers were charged Monday with second-degree murder in connection with the death of 67-year-old Kim Ngu Lieu, who was attacked in Montreal North last weekend.

Ngu Lieu was at a bus stop at the corner of St. Vital and Henri Bourassa Blvds. late in the evening on May 17 when police allege the three youths surrounded her, brutally beat her, and tried to steal her purse.

The accused -- two 16-year-olds and one 15-year-old -- were initially charged with robbery, conspiracy to commit robbery and attempted murder, but the charges were upgraded since Ngu Lieu died in hospital three days after the beating.

Prosecutor Karen Ohayon said the crown reserves the right to seek adult sentences for the teens if they are found guilty -- meaning they would receive life sentences with no chance of parole for seven years.