A Twin Cities man is charged with injuring an 81-year-old woman while trying to rob her outside a St. Paul drugstore last week, according to charges filed Thursday.

Isaiah J. Foster of Richfield was charged in Ramsey County District Court with first- and third-degree assault in connection with the mugging at the entrance to the Walgreens in the 1110 block of Larpenteur Avenue early in the afternoon on Dec. 23.

On Tuesday, five days after the attack at the drugstore, Foster is suspected of committing an armed carjacking in St. Paul's Crocus Hill neighborhood with two accomplices while a woman grabbed her 2-year-old from the vehicle, the charges read. Foster, who turns 19 on Friday, has been in jail since Tuesday afternoon in connection with the carjacking but has yet to charged in that incident.

"The actions of this young person caused significant trauma and injury to an elderly resident and spread fear throughout our community," Ramsey County Attorney John Choi said in a statement announcing the charges.

The woman who was attacked at the drugstore suffered a concussion and bleeding on the brain from the attack, and then had a dizzy spell while in the hospital, fell and broke her pelvis, the charges read.

Foster's mother turned in her son and told authorities "I'm 100% sure" that her son was the suspect she saw in store surveillance video that a family member brought to her attention.

"She does not trust police officers but wanted to do the right thing," the charges read. "She prayed about it and turned her son in. She loves her son but did not raise him like that."

Choi added, "I want to thank investigators for their work on this case and the mother of the young offender for doing the right thing by turning her son in to authorities."

Foster remains jailed in lieu of $50,000 bail ahead of a court appearance Monday. Court records do not list an attorney for him.

According to the complaint in the drugstore attack:

From her hospital bed, the woman told police that she was heading into Walgreens and felt someone pull on her purse. She yanked back, fell and remembered nothing afterward, believing she was knocked out. In an interview the next day, she reported that nothing was stolen.

Surveillance video confirmed the account the woman gave police and showed Foster running east on Larpenteur.

In the carjacking, the Ramsey County Sheriff's Office said that three armed men blocked a woman's car at her home in the 700 block of Osceola Avenue before taking it at gunpoint as the woman frantically pulled her toddler from the vehicle.

Deputies learned the vehicle was seen in another robbery in Minneapolis. When they located the vehicle and started following it near SE. Huron Boulevard and Delaware Street, a 17-year-old fled from the back seat. A deputy chased him on foot and arrested him near Huntington Bank Stadium.

Authorities from several departments apprehended Foster and the third suspect after learning that the stolen vehicle was in north Minneapolis.