Two people have been arrested in connection with at least one robbery at the University of Houston campus.

The UH police department said a group of former Elsik High School students is involved in at least one armed robbery in recent weeks. The suspected gunman, Ricardo Tangarife, was arrested on Thursday, officials said. He was charged with aggravated robbery.

UH police chief Ceaser Moore said Tangarife attacked a student at gunpoint on Wednesday in a campus parking lot.

"He got out of the vehicle and approached a student with a gun, and demanded their money and cellphone," Moore said. "He got back in the vehicle with a driver who we have not identified, and he drives to Memorial City Mall. And within 45 minutes of the robbery, he is making charges at stores."

Police also arrested Anthony Theus. He is accused of working at Sheikh Shoes at Memorial City Mall and knowingly allowed purchases with stolen credit cards.

Sue Ortiz

Investigators are searching for Sue Ortiz, a stripper. She is accused of using stolen credit cards. Police also called it "cleaning credit cards." A warrant has been issued for her arrest.

At least four others are believed to be involved. Police said they do not know if three robberies in one week on the UH campus are connected.

Before the robberies, the UH police force had 45 officers. The department has added an additional five officers because of the recent rash of armed robberies.

"I am concerned. I want the city and citizens to be safe. My job is to arrest offenders when they commit crimes like this on campus," Moore said.

More than 42,000 students are enrolled at the University of Houston.