Former state Treasurer Tim Cahill was indicted yesterday, adding to the growing list of Massachusetts politicians who have been convicted or indicted on criminal charges.

Cahill, 53, of Quincy, was indicted on charges of violating the state ethics law, conspiracy to violate the state ethics law, procurement fraud and conspiracy to commit procurement fraud.

Cahill, who as treasurer oversaw the state lottery, ran as an independent candidate for governor in 2010.

He is accused of using about 75 percent of the lottery’s $2 million budget to run ads in the final months before the 2010 election that promoted the lottery as a well-managed organization that gives funds back to cities and towns. Cahill did not appear in the ads and they did not mention his name.

Cahill approved the ads after focus groups showed his best image as a candidate would be of his good performance managing the lottery, Attorney General Martha Coakley said, calling it an “unwarranted and unlawful benefit to Cahill and his campaign.”

Cahill’s lawyer, E. Peter Parker, said the ads ran because the Republican Governor’s Association aired attack ads on the lottery, undermined the public’s confidence in the system and hurt sales.

“Not running the ads because the RGA or an overzealous attorney general might later question whether the ads might have benefited the Treasurer politically would have been the wrong thing to do,” Parker said.

Slippery slope?

Cahill is the first person charged since the state Legislature changed the state ethics law from a civil to a criminal crime, Coakley said.

When asked if Cahill’s indictment would set a precedent, Coakley said all politicians should be cautious.

“I think all elected officials need to be aware there will be greater scrutiny on taxpayer dollars,” she said.