CPI national secretary D Raja termed the charges as "serious" and demanded Central government to carry out the investigation through National Investigation Agency (NIA).
"It is a very serious issue. Whatever be the charges...The NIA should conduct a thorough probe into the matter to get at the root of the things," Raja demanded.
Eleven people were arrested from different places of the state on February 9 for being part of an alleged espionage racket being run from Pakistan to collect strategic information on important Indian establishments.
Targeting BJP over the issue, the AAP too had yesterday alleged that three of the accused were members of the saffron party and demanded probe in the matter.