Two people are in custody Tuesday following the fatal stabbing of a 67-year-old man in Sapulpa on Monday.
OSBI said information from witnesses and evidence collected at several scenes indicates 22-year-old Arnold Dean Howell, Jr. murdered Michael Mondier.
After requesting the public's help in finding Howell, deputies received a tip that he was in the parking lot of a West Tulsa Motel Tuesday afternoon.
Mondier was found dead inside his mobile home Monday.
"Deputies went to that location and found Mr. Howell and arrested him for first-degree murder and robbery," OSBI spokesperson Jessica Brown said.
Howell's sister Katherine Elaine Freeman was arrested for first degree murder Tuesday morning.
Both suspects were booked into the Creek County jail.
OSBI, Creek County deputies, Tulsa Police officers, and the DA's office have assisted in the case.