Durham, N.C. — Two men arrested after a high-speed chase committed at least 17 armed robberies, authorities believe. One suspect also killed a Duke University graduate student during a robbery, prosecutors argued Thursday.

Prosecutors said Stephen Lavance Oates Jr., 19, robbed Abhijit Mahato, 29, last Friday with a 9 mm handgun and stole $200, a wallet and cell phone from him. Police believe that Oates held up three other people at gunpoint that same day.

Investigators charged Oates and William Dozia Smith, 20, of Anthony Street, in at least 15 robberies going back to November. Many of the victims were Hispanic. They shot one robbery victim and injured another, police alleged.

The list of crimes stunned some as it was read at the suspects' first court appearance Thursday.

"You just think, how could this have happened in our city? How could someone commit this many crimes?" asked Mindy Solie, who owns the apartment complex where Mahato died.

State troopers arrested Oates and Smith after they led police on a high-speed chase through Durham and Wake counties Tuesday night.

Investigators believe that two 14-year-olds, caught in the car with Oates and Smith, helped the two men rob a couple at gunpoint Sunday night on Lambeth Circle in Durham.

Police said Oates and Smith were partners in at least eight robberies in western Durham since early January.

• Jan. 7, 6:55 p.m. at 3536 Mayfair St. – Two men approached two other men getting out of their car and robbed them at gunpoint. One victim was hit in the face during the robbery. The suspects fled with a cell phone, wallet and cash.

• Jan. 11, 10:33 p.m. at 881 Louise Circle – A man armed with a handgun robbed a man and woman in front of an apartment building. The robber fled with a cell phone, jewelry, bank cards and cash.

• Jan. 15, 9 p.m. at 1704 White Pine Drive – Two men robbed a Domino’s pizza deliveryman at gunpoint. The robbers stole a pizza and cash.

• Jan. 17, 6 p.m. at 1803 House Ave. – Two men wearing black, hooded sweatshirts robbed a man at gunpoint in front of an apartment building. They stole cash and a cell phone and then fled on foot.

• Jan. 18, 9 p.m. at 2920 Chapel Hill Road – Several men were working on a car when two men approached them on foot. The robbers took cash, wallets and cell phones.

• Jan. 19, 2:21 a.m. at 2920 Chapel Hill Road – Three men armed with guns stole cash from several men. The gunmen shot one victim in the leg before fleeing in a silver Mercedes and a white Ford Explorer or Expedition.

• Jan. 19, 11 p.m. at 2920 Chapel Hill Road – Two men used a gun to threaten a man as he was getting out of his car. The robbers stole cash and debit cards and fled on foot.

• Jan. 20, 7:08 p.m. at 880 Louise Circle – A man armed with a handgun robbed one man. He stole cash, a cell phone, bank cards and an iPod.

News of Oates’ arrest came as Duke University officials and police met with the community about a rash of crimes, including armed robberies. Since Jan. 1, there have been more than 70 robberies in Durham.

"We've not stopped. We're going to continue investigating," Durham Police Chief Jose Lopez said. "We're going to get to the others involved in the robberies."

Lopez said investigators believe other people had a share in committing those 70 robberies, but were still checking if Oates and Smith were involved in other incidents. More arrests in the death of Mahato are also possible, Lopez said.

Police believe several robberies might not have been reported. Anyone who has been the victim of a robbery should call 911 and make a report. Anyone with information on the recent robberies should call Investigator R.J. Guardino Jr. at 919-560-1020, ext. 236.

Solie said the active pursuit and apprehension of Oates restores some sense of security for her.

"I feel 100 percent better," Solie said.

A judge denied Oates bond on the murder charge and set his next court appearance for Jan. 31. Smith was being held on a $3.1 million bond.

Oates was charged with breaking and entering in 2005 and 2006. He was also charged in 2006 with assault on a female, according to court records.

Mahato, originally from Tatangar, India, was studying for an engineering doctoral degree in computational mechanics at Duke’s Pratt School of Engineering. He was in his second year.

A memorial service for Mahato was scheduled for 1 p.m. Friday on Duke's campus.