The office announced its conclusion in a letter dated Nov. 7, the day after Begaye lost his District 4 seat to Republican opponent Sharon Clahchischilliage during the general election.
"Based upon the material provided to us we find insufficient evidence to prosecute any criminal charge against Representative Begaye," a letter written to Ra l Burciaga, director of the Legislative Council Service, said.
The office investigated Begaye for a travel expenses in which he received reimbursements from both the state and the National Conference of State Legislatures.
The reimbursements were for legislative trips to Phoenix in 2010; Scottsdale, Ariz., in 2009; San Francisco in 2009; Palm Springs, Calif., in 2006; and Sonoma, Calif., in 2005, according to the Albuquerque Journal.
Neither the State Mileage and Per Diem Act nor the criminal code covering misappropriation of public funds explicitly prohibits this practice, according to the office's letter.
The office did, however, make a point to discourage it.
"The appearance of impropriety holds an elected official to the highest standard of behavior when engaged in their duties. The specter that public funds were improperly used or obtained casts a dark shadow over the entire Legislature," said David Pederson, general counsel for the Attorney General's Office, in the letter.
We suggest (Legislators) be limited to receiving expense reimbursement from only a single entity for any particular trip," Pederson wrote.
Both Democrats and Republicans agreed that the investigation likely hurt Begaye's campaign, ever garnering criticism from Clahchischilliage toward the end of her own campaign.
The news in October that Begaye tried to help his daughter receive a lenient ruling in July after she was charged with a DWI in San Juan County also likely did not help his campaign.
Clahchischilliage won by a landslide with more than 60 percent of the nearly 9,500-vote during election night, even though Clahchischilliage took in about $12,000 less in campaign contributions.
Clahchischilliage received less than $24,000 in contributions. Begaye received more than $36,400.
Begaye did not respond to phone calls or email Thursday to comment on the report.
Clahchischilliage, on the other hand, was shocked by the Attorney General Office's conclusion.
"Double dipping is not illegal? That's absurd," said Clahchischilliage on Thursday. "That's still wrong. It's still not right."