Kundara Circle Inspector R Shabu and sub-inspector Rasheed were suspended from service for dereliction of duty and lapses in investigation, Vijayan said while replying to a submission by Opposition Leader Ramesh Chennithala in the Assembly.
The girl's body was found hanging from the window of her mother's house at Kundara on January 15.
Vijayan said the post-mortem report confirmed that the girl was sexually abused.
He also said the girl's relatives were not cooperating with the investigation.
A case has also been registered, he said, adding that the government would take stern action on crimes against children and women.
The chief minister also said the society has to be vigilant against this "growing perversion" in the state.