SAN DIEGO (Reuters) - A great-grandmother who sold do-it-yourself asphyxiation kits from her home in California pleaded guilty on Friday to a misdemeanor tax-related offense stemming from an investigation of her mail-order business.

Sharlotte Hydorn is interviewed by local media outlets at her home in El Cajon, California in this May 26, 2011 file photo. Hydorn, who has been selling do-it-yourself asphyxiation kits from her home in California, pleaded guilty on December 2, 2011 to a misdemeanor tax-related offense stemming from an investigation of her mail-order business. REUTERS/Marty Graham/Files

Sharlotte Hydorn, 93, a retired public school science teacher, admitted failing to file a federal income tax return from 2007 through 2010, years in which investigators said at least seven customers used her kits to commit suicide.

Prosecutors said Hydorn sold about 1,300 of the devices during that time but had agreed to stop making or selling the kits as part of her plea deal.

The San Diego County district attorney, who was a party to the settlement, agreed not to prosecute Hydorn for her role in any of the six known deaths that occurred in that county.

Federal prosecutors said they would recommend probation and a fine as punishment.

Hydorn, whose San Diego-area house was raided in May by federal agents seizing documents, computers and sewing machines, has said her so-called “exit kits” were intended to help terminally ill people end their lives with dignity in their own homes.

The product, sold for $60 each including instructions and shipping, consisted of a plastic hood that closed around the neck and tubing that connected the hood to a tank of helium or other inert gas that users had to supply themselves.

She acknowledged selling the kits for the past 20 years under the brand name GLADD, which stands for Glorious Life and Dignified Death, without performing background checks or screening the individuals who ordered the apparatus. But she has insisted she made little money from the enterprise.

Still, Leslie DeMarco, a special agent in charge of the Internal Revenue Service field office in Los Angeles, said Hydorn “was operating a for-profit business without regard to the identity of her clients, their current medical condition or the federal tax laws.”

“It was clear that Hydorn, in fact, has no way of knowing if a purchaser was simply depressed or a minor acting without the consent or guidance of their parent,” DeMarco said.

‘A COMMITTED PERSON’

Hydorn’s lawyer, Charles Goldberg, said she never deposited payments from her patrons, and that FBI agents found hundreds of uncashed checks and envelopes of cash in her home.

“She was a committed person with strong beliefs that a person had a right to determine the quality of their life, particularly in the last days,” Goldberg said.

Hydorn has said her interest in helping the terminally ill stemmed from the loss of her husband to colon cancer in 1977.

The income she failed to report to the IRS was mostly from her retirement pension, Social Security and rent from two small apartment units, he said.

Goldberg added that “the great majority of people who purchased the kit from her never used it.”

“It was an alternative in the event that their life became so unlivable that they wanted to end it,” he said.

Hydorn made headlines after one of her mail-order customers in Oregon, Nicholas Klonoski, 29, described by his family as suffering from depression but otherwise healthy, used one of her kits to kill himself in December 2010.

Outrage over that case led Oregon state lawmakers to pass legislation to ban sales of such devices, even though Oregon is one of two U.S. states with laws on the books legalizing physician-assisted suicide for people with incurable, fatal illnesses.

Federal investigators said they have documented that six other people in San Diego County alone who purchased her kits used them to commit suicide during the past four years. The federal prosecutor’s statement announcing the plea deal said the four most recent, all from 2010, ranged in age from late 40s to the mid-80s, and none was terminally ill.

The misdemeanor to which Hydorn pleaded carries a maximum penalty of a year in jail and a $100,000 fine. Prosecutors said in court documents they would recommend five years of supervised probation and a fine at the “low end” of federal guidelines.

The IRS estimates Hydorn owes $15,000 to $30,000 in back taxes, which she has agreed to pay. She remains free on $10,000 bond. A sentencing hearing was set for February.