Atlanta — The suspect in the killing of a nursing student on the University of Georgia campus used an object as a weapon in the crime that caused blunt force trauma and is accused of "disfiguring her skull," according to newly filed arrest affidavits.

Jose Ibarra, who faces multiple murder and assault charges, is also accused of dragging 22-year-old Laken Riley to a secluded area on Thursday, according to one of the affidavits obtained by CBS News. The allegation that he dragged Riley's body was filed to support the charge of concealing the death of another person.

Authorities haven't said exactly how Riley was killed, only that her death was caused by blunt force trauma. Further details about the type of object used, or exactly how she was killed, aren't included in the affidavits for arrest.

The affidavits, filed in Athens-Clarke County Superior Court, state that the crimes were committed between 9 a.m. and 1 p.m. on Thursday.

Ibarra, 26, is a Venezuelan citizen who immigration authorities say unlawfully crossed into the United States in 2022.

Riley was a nursing student at Augusta University's Athens campus, after starting her college career at the much larger Athens campus of the University of Georgia. She was found dead Thursday after a roommate reported she didn't return from a morning run in a wooded area of the University of Georgia campus near its intramural fields.

Hundreds of students and faculty members gathered Monday afternoon for a vigil for Riley organized by her sorority sisters at the University of Georgia campus. Many people cried and members of Alpha Chi Omega held carnations, a symbol of the sorority.

"Laken showed devotion with every aspect of her life," said Chloe Mullis, president of the University of Georgia chapter of Alpha Chi Omega. "Doing things halfway just wasn't an option. We lost one of the brightest lights that has ever been."

Republicans including former President Donald Trump and Georgia Gov. Brian Kemp have used the killing to attack the immigration policies of President Biden. Georgia Democratic Senate Minority Leader Gloria Butler called the Republican response to Riley's death "appalling," saying the GOP is to blame for scuttling a bill in Congress that would have toughened immigration enforcement. 

Despite the heated rhetoric, researchers' analysis of crime data in several studies has shown that undocumented immigrants have lower rates of violent crime compared to U.S. citizens. 

U.S. Immigrations and Customs Enforcement says Ibarra was detained by the Border Patrol on Sept. 8, 2022, after entering from Mexico near El Paso, Texas. He was released for further processing, according to ICE. It's unclear if Ibarra applied for asylum.

According to ICE, Ibarra was arrested by New York police on Aug. 31, 2023 and charged with acting in a manner to injure a child less than 17 and with motor vehicle license violation. Ibarra was released before ICE could ask New York officials to hold him until immigration authorities could take him into custody, ICE said. New York officials said Sunday they had no record of the arrest.

The White House expressed condolences to Riley's family and referred questions about the case to ICE and local law enforcement.

Separately, Athens-Clarke County District Attorney Deborah Gonzalez announced late Monday that she's appointing a special prosecutor for case, CBS Atlanta affiliate WANF-TV reports. Gonzalez said she's naming attorney Sheila Ross, who she described in a statement as "a knowledgeable and well-respected trial attorney with the expertise ready to bring justice on behalf of Laken Riley."