The woman sub-inspector had allegedly made forged signature of assistant commissioner of police (ACP) M Harshwardhan, posted at Dabri sub-division, on documents which were to be furnished before a court, the police said.
The 35-year-old sub-inspector was found have used the forged signature in three other cases too, they said,
"The matter became known when Harshwardhan found his signature on a file relating a case of cheating. Suspicious of it, the ACP made initial probe only to find it was not his signature.
A case has been registered at Dabri police station under relevant sections and investigation into the matter is underway, police said.
Attached to Barakhamba police station presently, the 2008 batch sub inspector has been questioned in connection with the matter, cops added.