A relative of Leonidas Tzanis said the former Socialist deputy interior minister hanged himself, The Financial Times reported.
Tzanis, one of 35 politicians identified as under investigation in a tax-evasion scandal, is alleged to have taken payments from illegal slot machine operators for about the last 10 years, the newspaper said.
Prosecutors, the Greek Parliament and financial regulators have announced plans to go after suspected tax evaders. Protests of economic conditions in Greece often feature chants of "Thieves! Traitors!" as members of the public lose patience with tolerance of tax evasion.
A study by researchers at the Virginia Polytechnic Institute and the University of Chicago's Booth School of Business found self-employed Greek professionals fail to report income totaling 28 billion euros, or about 15 percent of Greece's national output, the newspaper reported.
"Our evidence suggests that industries with a low paper trail and industries supported by parliamentarians have more tax evasion," the study found.
Friday's session of Parliament was interrupted by an outburst from lawmakers from the neo-Nazi Golden Dawn Party, who were elected in June.
"You're all thieves! You've been robbing Greece for 20 years -- now you have to pay!" the Golden Dawn members said.