IOWA CITY, Iowa (AP) — The son and boss of an Iowa grandmother charged in a 25-year-old homicide said Thursday that they were stunned by her arrest and confident that she's not the killer.

Authorities arrested 55-year-old Annette Cahill of Tipton, Iowa two weeks ago, charging her with first-degree murder in the 1992 beating death of her friend Corey Wieneke. They say the charge came after an unidentified new witness gave police information implicating Cahill, who has been jailed on a $1 million bond and faces life in prison if convicted.

Cahill has worked since 2009 as a proofreader and customer service assistant at the Police Law Institute, which provides online training courses that are taken monthly by thousands of police officers. Her boss, David Oliver of North Liberty, Iowa, said her arrest came as a "complete and utter shock." He said the two had talked years ago about the impact that Wieneke's death had on her, and how she had been long ago cleared as a suspect.

"I've known her for a better part of a decade, and this is not the person that I know," said Oliver, who recently donated $1,000 toward the costs of her legal defense. "She believed fully in our mission. That's why I think it's a double shock. From that standpoint, she was very much about due process and how to do it. She's very pro-law enforcement."

Wieneke, a 22-year-old bartender at his family's tavern, was found dead on the floor of his bedroom in rural West Liberty, Iowa in October 1992. Police say that he was beaten to death with a baseball bat that was found near his home. Police allege that Cahill had been in a sexual relationship with the engaged Wieneke, and that they had a heated argument about his involvement with another woman in the early morning hours of Oct. 13, 1992, hours before he was killed.

A witness came forward last year claiming Cahill had implicated herself in the death in 1992, prompting authorities to re-examine the case. Investigators say Cahill has given conflicting accounts of where she was during the homicide, and was aware Wieneke was killed with a bat before that was public knowledge.

Cahill is now a mother of three adult children and a grandmother of four who had no prior criminal record. Her son, Jon McCrabb of Fort Morgan, Colorado, was 7 years old when Wieneke was killed, and he remembers his mother mourning the death and getting routine updates from investigators. He said Cahill and Wieneke used to date.

"I remember throughout my childhood her talking about her best friend being killed," said McCrabb, 33, who recently launched a GoFundMe campaign to raise money for her defense. "There is no doubt in any of our minds that she didn't do this."

He described Cahill as a "sweetheart" who has helped him through tough times, a quilter, a great cook and a crossword puzzle enthusiast. He said he hasn't been able to speak with his mother since she's been in jail but others who have say "she's just overwhelmingly sad and upset and can't believe this has happened."

Cahill recently retained defense lawyer Clemens Erdahl and his law firm to represent her. McCrabb said that Cahill had been planning to go with a public defender so that her family wouldn't have to bear the expense, but was convinced that she should hire more experienced counsel.