"As per preliminary investigation we haven't found any political angle in the murder case," ADG (Law and Order) Banibrata Basu said.
"We are looking into the call list of his mobile phone. We have found some phone numbers of women. We are looking into it," Basu said.
Sarkar was shot dead by four motorcycle-borne gunmen when he was on a morning walk.
The Trinamool Congress denied any connection with the killing and blamed it on CPI(M) internal rivalry.
Left Front chairman Biman Bose had earlier accused the TMC of the killing and described it as it a gameplan to wipeout the opposition from West Bengal.