The parents of a missing Indiana University student are waiting anxiously for authorities to identify a human skull found submerged in an Indianapolis river -- a process that will take at least six to eight weeks, the Marion County coroner told FoxNews.com.

Chief Deputy Coroner Alfarena Ballew said the skull, found last week in the White River, appears to have been in the water "about a year." Ballew said it will take several weeks to determine the race and gender of the skull -- and possibly the identity if authorities are able to extract DNA or match it with dental records of missing persons in a national database. 

Lauren Spierer, 20, of Greenburgh , N.Y., disappeared from Indianapolis a little more than a year ago on June 3, 2011. She was last seen in the early morning -- standing barefoot and alone -- on the intersection of 11th Street and College Avenue in Bloomington, Ind., according to the woman's acquaintance and college classmate Jay Rosenbaum.

Rosenbaum claims he watched the petite, blonde-haired student walk from his building toward her off-campus apartment complex some three blocks away around 4:30 a.m. the morning she disappeared. Rosenbaum’s last reported sighting of Spierer followed a night of partying among a loose group of college friends and acquaintances.

The skull was found by a local fisherman near the east bank of the White River in an area about 60 miles from the street corner where Spierer was last seen. Ballew told FoxNews.com that the skull is now with a forensic anthropologist, who is working to determine the age, race and gender of the victim. Once that is established, authorities will try to match it with dental records of missing persons who fit the profile, she said. They will also try to extract DNA from it.  

"We have never had a case where we've had to extract DNA from a skull only," Ballew said, noting that authorities have not recovered any other body parts.

Spierer's disappearance touched off a massive search by air, land and water for any trace of the young woman. 

Spierer's father, Robert, told the Journal News that "We don’t have any information" on the latest find and that "We’re just waiting like everybody else."

On a Facebook page devoted to the search for their daughter, the Spierer family wrote: "In the days ahead, a family will have answers they have been desperately seeking. Will it be ours? When will you end this nightmare for our family? We will never give up.

"We are just as determined as we were on June 3, 2011. You need to know that. It's our promise to you. For now we continue to wait…. The Spierers."

FoxNews.com's Cristina Corbin contributed to this report.