A Granby woman has pleaded guilty to second-degree involuntary manslaughter in connection with the methadone overdose death of her 22-month-old son.

Elizabeth Farnam, 34, was initially charged with second-degree murder in the June 2012 death of Logan Crow. Farnam entered the guilty plea during a disposition hearing on Monday.

Farnam told investigators at the time she had dropped a methadone pill while the child was sitting on her lap during church. The toddler began sweating heavily on the drive home and was put down for an afternoon nap, but not checked until the next morning.

A toxicology report showed the child died from an overdose of methadone, prescribed mainly to treat heroin addiction. Investigators said Farnam obtained the drug illegally.

A sentencing hearing has been set for Dec. 2.