ROME -- Prime Minister Silvio Berlusconi is now confronting perhaps his most formidable adversary: his past.


The post-election victory handshakes have been replaced by the tightening grip of prosecutors as they delve into alleged bribe-paying at his media and retail company.


Supporters are waving goodbye, disillusioned by Berlusconi's strong-arm style and concerns about possible overlapping loyalties between business and politics.


And now the once supremely confident media magnate is struggling to keep his coalition from self-destructing. But the problems keep multiplying and are starting to hit closer to home.


Prosecutors are digging into allegations that tax examiners were bribed in exchange for approval of doctored books at Fininvest SpA.


Berlusconi's younger brother, Paolo, is among three people charged so far in the probe. Prosecutors have hinted that more arrests are possible.


Berlusconi moved to defend his company. "I can say that if all business were run like Fininvest, there wouldn't be problems of public morality in Italy," he told reporters. "It's certain that in a very big company, if you want to find something out of place, sooner or later you'll find it."


The scandal packs a double-barrel blow for Berlusconi. It could undermine an image that proved immensely popular to voters -- an entrepreneur who prospered outside Italy's cozy and corrupt business world. Also, it suggested Berlusconi keeps a keen interest in Fininvest affairs even though he insists he has cut all management ties.


On Sunday, Berlusconi held a closed meeting at a villa outside Milan with Fininvest's president and government officials who used to work for the company. Critics cried conflict of interest. Berlusconi claimed it was just a meeting of old friends.


The tax bribery investigations came as Berlusconi was picking himself up after his first major political setback.


Intense internal protests and public outrage forced Berlusconi to back off a July 13 decree that would have dropped pre-trial detention for suspects in political corruption cases and other white-collar crimes.


The bribery probes have focused on Fininvest and some other top commercial and financial firms in northern Italy.


Fininvest's top tax official, Salvatore Sciascia, reportedly told prosecutors that Paolo Berlusconi approved funds to pay off tax examiners in exchange for their stamp of approval on fraudulent records. An arrest warrant was issued for Paolo Berlusconi on Tuesday. Immediately, opponents questioned whether Berlusconi anticipated the bribery probe and tried to spare friends and his brother jail time with the decree limiting preventive detention. Berlusconi said he was worried about civil rights violations