Former Massachusetts state treasurer Timothy P. Cahill was directly involved in the state lottery's decision to launch a $1.65 million taxpayer-funded advertising blitz seen as benefiting his campaign for governor last year, according to e-mails and other documents obtained by local media.

In August 2010, Cahill met for lunch with Hill Holliday chief executive Michael J. Sheehan, according to e-mails between lottery officials and the Boston firm. Following that lunch, Diane Anderson, then the lottery's marketing director, and Hill Holliday executives scrambled to put together new television and radio ads.

While the original plans called for ads that focused on specific lottery games, the new ones promoted the lottery's management, which is overseen by Cahill as state treasurer. Though they do not mention Cahill by name, the revamped ads portrayed the agency as a well-run operation that returns billions of dollars to local communities.

As one e-mail noted, the change in ad strategy was directed "per the treasurer."

Other e-mails said Sheehan sent the script for the ads to Cahill and suggest the treasurer and the Hill Holliday chief executive had gone over the details of the production and the purchase of media time. The documents were obtained through the state's public records law.

Cahill's lawyer acknowledged that the former treasurer was involved in the decision to switch the ad campaign, but said Cahill felt it necessary to help bolster the lottery's image.

State law prohibits government officials from using their position or public resources to further their political career. It calls for heavy fines and up to five years in prison for those who use substantial resources for their campaigns with "fraudulent intent."

Cahill himself rarely if ever used e-mail, according to his former aides, but the communication that took place among his lottery staff members documents Cahill's active participation in the change in lottery ad strategy. The exchanges also include revised advertising budgets and the ad scripts.

Until now, it appeared that only Cahill's political campaign staff had been involved in orchestrating the advertisements, sending several e-mails and a text message to Hill Holliday about the plan as they tried to help Cahill's troubled campaign for governor.

The ads began running in late September and were scheduled to end in late November, consuming more than 80 percent of the lottery's entire annual advertising budget, just a few months into the start of the fiscal year.

But Cahill pulled the campaign in mid-October under pressure from Attorney General Martha Coakley, who is investigating possible criminal wrongdoing in the media campaign. As it has in the past, her office declined to comment on the probe.

The Boston Globe reported in April that prosecutors in Coakley's anticorruption unit have subpoenaed thousands of documents and e-mails from the lottery and the state treasurer's office related to the campaign. Several weeks ago, the lottery turned over some 30,000 e-mails to Coakley's office.

On the same day last August when Cahill and Hill Holliday's Sheehan had lunch, Amy Hardcastle, senior vice president at the firm, told Anderson, the lottery's marketing director, that she had given Sheehan cost breakdowns for the ads to show Cahill at their meeting.

"I gave Mike the same permission production/media numbers I gave you, so I'm sure he shared them with the treasurer," Hardcastle wrote in an e-mail. Permission ads are designed to allow players to feel good about purchasing tickets by promoting the state lottery's image, as opposed to highlighting certain games. Sheehan declined to comment yesterday.

Three days after that lunch, a Hill Holliday account manager sent an e-mail to the lottery laying out three budget proposals for ads, to find out how much they wanted to spend and on what kind of media outlets.

Three days later, Sheehan forwarded the script for the television ad to one of Cahill's top gubernatorial campaign operatives, Scott Campbell, for the treasurer to review.

That same day, Hardcastle e-mailed Anderson: "We pulled production, talent, media, and fee numbers to support a permission campaign per the treasurer."

Cahill's lawyer, Joseph L. Demeo, defended Cahill's decision to switch ad campaigns, calling it an effort to help offset a dip in sales and rehabilitate the lottery's reputation, which had been badly tarnished in a separate, $2 million campaign run by national Republicans that attacked Cahill and the lottery's image.

"The treasurer would have been remiss if the lottery did not act to protect crucial state revenues," Demeo said. "The decision to run the ads was both sound business judgment and completely legal."

Though they do not mention Cahill by name, they clearly appear to bolster his leadership of the agency. They cite the $7.3 billion that the lottery has generated for municipalities since 2003, the year Cahill took office.

And they end with the phrase: "That's the result of a consistently well managed lottery. And luck has nothing to do with it."

His campaign staff's strategy to bolster the treasurer's image through lottery ads was first revealed in internal campaign communications among his political advisers that were made public in a lawsuit last fall.

Those earlier released e-mails, as well as a text message among his staff, suggested only a limited involvement on the part of the treasurer.

Demeo argues that state campaign finance regulators have determined it is legal that an elected public official can use public resources to respond to criticism of the official's record, in Cahill's case, the attack ads by Republicans.