The authorities are not publishing any further arrest information to ensure the integrity of the investigation. Collins-Smith's death is being investigated as a murder, the statement said. Information about O & # 39; Donnell's lawyer was not immediately available.
Collins-Smith was found shot dead on June 4 at her home in Randolph County.
She was one of two former Republican Senators who were found dead in their homes within two days. The next day, after reports of gunfire, Jonathan Nichols was found dead in his home in Oklahoma.
The deaths seem unrelated.
Arkansas Gov. Asa Hutchinson expressed her condolences to her loved ones.
"She was a good person who served with passion and conviction in public," Hutchinson said. "The First Lady and I express our sincere condolences to her family and friends during this difficult time."