Marsha Cordero, election supervisor of Negros Occidental, has asked Resurreccion Borra, the Commission on Elections commissioner in-charge of Western Visayas, to call for an immediate probe on the incident.
Cordero said one DCM was forced open, while the contents of another one was deleted.
Clearly, she said someone wanted to access the master files in the first DCM but not knowing the password, he or she resorted to opening the back of the machine to get the hard disk.
Talisay City Mayor Anthony Lizares said the attempts to tamper with the DCMs appeared to be politically motivated.
Lizares camp had petitioned for the replacement of city election registrar Susan Araiza for being allegedly partial to another candidate.
While the DCMs have back-up files, Cordero said they are unsure if these are the same as the machines actual contents.
"We dont know if the motive was personal or political," she said.
Pending the investigation, Cordero has asked the police to guard the Comelec offices in Talisay City.
Meanwhile, Cordero said she would verify with Borra the actual number of ballot boxes shipped to Negros Occidental after local campaigners of opposition presidential bet Fernando Poe Jr. alleged that 200 ballot boxes were missing.
Poes campaigners have asked Rodolfo Parreño, provincial chairman of the FPJ movement, to investigate it.