A 91-year-old US woman who startled authorities by making and selling suicide kits pleaded guilty Friday to failing to file federal tax returns. Sharlotte Hydorn acknowledged she made more than $150,000 from various sources since 2007, including from the sale of helium kits that people could use to kill themselves.The suicide kits drew national attention after the death of 29-year-old Nick Klonoski, who used one of Hydorn’s “helium hoods,” prompted Oregon lawmakers this year to consider outlawing the sale of such kits.During a May raid on Hydorn’s home in California, federal agents seized suicide kits that sold for $40 each and essentially consisted of a plastic bag and clear tubing. The kits caused death by helium asphyxiation once the hood was attached to a helium gas source — which was not part of the kits.Hydorn said she sold the kits under the name “GLADD Group.” Court documents say she sold more than 1,300 kits to people across the United States and abroad.“This prosecution puts an end to the defendant’s trafficking in these dangerous, unregulated devices,” US Attorney Laura E. Duffy said.Activists have long argued about a person’s right to take their life, and what exactly it means to assist them. But the laws in the US are often vague and provide little detail as to what “assist” or “aid” means. Legislative efforts have been in the works to define suicide assistance. After the raid on her home, Hydorn told The Associated Press that she isn’t responsible for who uses the kit and is only trying to help people in pain. The retired teacher told authorities she thought the kits would be used by the terminally ill. Prosecutors, however, said she took no steps to verify the physical condition, age, identity or mental state of her customers and therefore had no idea whether her kits were being bought by people suffering from depression or by minors acting without the consent of an adult. Prosecutors say Hydorn also tried to hide the true purpose of her kits on US Customs forms by listing them as an “orchid humidifier,” “beauty bonnet” or “plastic rain hood.”Prosecutors say a document seized at Hydorn’s home during the raid stated that the GLADD Group preferred customers to pay with money orders because they “don’t leave a paper trail.” It also stated she would prefer to not have her name in the check registers of those who “have hastened their deaths.” Hydorn said she had been in business for three years and sold up to 60 kits a month. Investigators determined that the kits were sold to at least 50 people in San Diego County since 2007 and that four of those people last year used the kits to commit suicide. None was terminally ill, according to investigators.As part of her plea deal, Hydorn agreed to pay $26,000 in outstanding taxes. A judge ordered her released on $10,000 bond on the condition that she not assist any suicides. She is scheduled to be sentenced Feb. 16.