Cobb County school board member David Chastain violated campaign finance law when he accepted overly large donations last year, a state commission found.

Chastain, who was reelected to his position in November, must pay a fine to the state and refund $2,500 in contributions.

Chastain, a Republican, faced Democrat Catherine Pozniak in a race last year for the Post 4 seat covering the northeast portion of the county. Pozniak filed a complaint with the Georgia Government Transparency and Campaign Finance Commission in October. The commission does not investigate complaints made within 30 days of an election until after the election results are certified. The commission concluded the investigation in June.

After the complaint was filed, Chastain contacted the commission and admitted to making a mistake, according to an order from the commission. Chastain called the complaint “baseless and politics at its worst” in a news release when it was filed.

Chastain accepted contributions that were too large from the campaign of state Rep. Ginny Ehrhart, R-Powder Springs, and from a lawyer connected to the district’s controversial redistricting process. He failed to file a form that would have permitted the contributions to be split between the primary and general elections and therefore under the allowable limit, the commission found.

“I missed a form that I should have caught and that’s that,” Chastain told The Atlanta Journal-Constitution on Friday. He added that he’s already paid a $250 civil penalty to the commission and returned $1,500 to Ehrhart and $1,000 to Jonathan Crumly, the attorney.

The state order was first reported by the Cobb County Courier.

Chastain has been on the school board since 2014, and in November won another four-year term.