Napa County prosecutors are going after a local winery for illegally hosting commercial events, filing civil charges against St. Helena's Leonardini Family Vineyards for holding wedding receptions and other events at its Fawn Park Vineyard and Barn off Silverado Trail.

In a lawsuit that follows months of back and forth between company officials and county officials, Napa County prosecutors say Leonardini Family Vineyards -- which owns Whitehall Lane Winery in St. Helena -- broke zoning regulations prohibiting commercial activities in the agricultural preserve, fire code regulations, maintained a public nuisance and engaged in unfair business practices.

Prosecutors are seeking a preliminary injunction against the vineyard company at a court hearing later this month.

Company representatives did not return phone calls requesting comment.

But in a Feb. 17 letter to county officials, winery owner Thomas Leonardini denied hosting commercial events up to that point in time, saying only that it had hosted parties for neighbors, friends and the community.

"We are model citizens," Leonardini wrote. "It is my intent, as well as the intent of my children and grandchildren, to be contributing members if this community. To send such a letter to me and verbally threaten me with an action from the district attorney is out of line."

Yet Leonardini also wrote, "We have booked commercial activities for profit starting this summer."

According to court papers, the district attorney's office subpoenaed the company's business records. Prosecutors charge those records revealed three short-term rentals of the property took place last year, one in May and that the Leonardinis planned to hold nine more commercial events -- "apparently weddings" -- on the property between Aug. 19 and Oct. 14.

Prosecutors also submitted to the court what they say are copies of reservation agreements. One, for a three-night rental of Fawn Park leading up to an event on Sept. 3, quoted an event price at $6,500 and nightly rental of $850 per night, which included brunch.

Some caveats to the deal stipulated that only Whitehall Lane wines could be served at the event and that amplified music must stop at 10 p.m.