Investigators found text messages in which Ma expressed her frustration when the student victim didn't text her back and became jealous when he spoke to other girls, among other evidence.
Earlier on Wednesday, Credit Suisse' shares plunged after Saudi National Bank, which was Credit Suisse's largest investor, refused to offer further financial assistance.
Timothy Bliefnick, 39, is accused of breaking into the home of his estranged wife, Rebecca Bliefnick, and fatally shooting her. She was found dead at her Quincy, Illinois, home on Feb. 23 after she failed to pick up the kids.
Thomas visited his grandma that day, but he acknowledged that the trip came during a busy time because of a recent transfer from California to Florida.