A 7-month-old baby who was the lone survivor of an alleged attack by his own mother has succumbed to his injuries, authorities announced Friday. The baby boy had suffered traumatic injuries in the alleged attack earlier this week that left two other children, aged 5 and 3, dead. Prosecutors say the children's mother, Lindsay Clancy, strangled the children before jumping from a window in an apparent suicide attempt. Police have been probing whether Clancy was suffering from postpartum psychosis when she allegedly attacked her children. The 32-year-old is currently in recovery in a Boston hospital while in police custody on murder charges, as well as three counts of strangulation or suffocation, and three counts of assault and battery with a deadly weapon.