By Isabella Biedenharn
April 23, 2015 at 01:53 PM EDT
Seattle Times, Betty Udeson/AP

True crime author Ann Rule’s two sons allegedly coerced their bestselling mother out of $100,000, authorities say, according to the Huffington Post. The report says that one son even “demanded money while she ‘cowered in her wheelchair.'” Michael and Andrew Rule have been charged with domestic violence crimes in Ann’s home of King County, Washington. 

84-year-old Rule, who has written 30 New York Times bestsellers, including The Stranger Beside Me, about serial killer Ted Bundy, has suffered ill health since October of 2013, when she broke her hip in a fall. According to documents the Huffington Post received from the King County Prosecuting Attorney’s Office, Rule is “on oxygen at all times,” is prone to bouts of “extreme confusion,” and is “vulnerable to undue influence.” The author is “unable to perform many activities of daily living without assistance.”

On March 2, Rule’s son-in-law, Glen Scorr, reported to the prosecutor’s office that he suspected Rule was being “financially exploited” by sons Michael and Andrew Rule. After a joint investigation by the King County Sherriff’s Office and the Normandy Park Police Department, authorities found that four of Rule’s children “receive an estimated $25,000 monthly salary through her corporation, Rule Enterprises LLC, for ‘assigned responsibilities,” HuffPo reports.

Michael Rule’s documented abuses include pressuring his mother into giving him money above his monthly salary, forging her signature on checks to him totalling $103,628, engaging in verbal abuse, and screaming at her in anger and smashing a cell phone. One of Ann Rule’s caregivers actually quit because she was “afraid of Mike and his volatile temper,” the documents obtained by the Huffington Post state. Michael lives adjacent to Ann’s property.

Charges against Andrew Rule are equally heavy: According to the documents, “Andy would pester and bully Ann relentlessly for money, sometimes threatening suicide, sometimes trying to make her feel guilty, sometimes screaming obscenities at her, until she would finally give in and write him a check.” Ann was granted a protection order against Andrew, which he was arrested for violating on March 27. According to the L.A. Times, when a reporter for KIRO-TV news asked Andrew to comment on the charges, he denied them and said, “Basically, I used to have a gambling problem but I don’t anymore, and I have absolutely no idea why I was pulled in at the same time my brother was.”

Rule is a former Seattle Police officer. Her most recent book, Practice to Deceive, came out in 2013. Michael and Andrew were both charged with two counts of theft in the first degree, which has a maximum penalty of 10 years in prison, and one count of forgery, which comes with a five-year prison sentence at maximum.