It was an ordeal that lasted 19 hours. In that span, a man bound a Columbia University graduate student in her apartment, raped her, doused her with hot water and bleach, slit her eyelids and finally set a fire before fleeing, police said.

Police pressed a manhunt for the assailant in the April 13 attack, with investigators hoping any surviving DNA and a $12,000 reward for information leading to an arrest would produce fresh leads.

The victim, who managed to free herself before the fire spread, was still in the hospital Thursday, police said.

The woman was nearing her degree at the Graduate School of Journalism when the attack occurred at her apartment more than 20 blocks north of the Ivy League campus in upper Manhattan, classmates have said. Dozens paid tribute to her Monday with a candlelight vigil.

Female students throughout the school were rattled, especially because the attacker was is still on the loose, said Lindsay Miller, 23, an architecture student who, like the victim, lives several blocks from the campus.

"It makes you nervous," she said. "I find I'm walking faster and looking over my shoulder."

Witnesses told police they had spotted the attacker loitering around the victim's building on the night of the attack. At about 9:30 p.m., he slipped inside, got on an elevator with her and pushed a button for a different floor than hers, police said.

He followed her out of the elevator and pretended like he was lost, police said. Then he followed her to her apartment door and forced his way inside, where he beat her.

Over the next several hours, he raped her on her futon bed, tied her up with computer cables, force fed her drugs and alcohol and used a knife to slit her eyelids, police said.

Before fleeing at about 4:30 p.m. Saturday, he ignited a corner of the futon, unknowingly providing his victim a means to escape and get help from a building handyman, police said.

"It appears she was able to escape as a result of the fire," Police Commissioner Raymond Kelly said. "She was tied, and the flame was used by her to break the bond."

Investigators recovered a videotape from a neighboring market showing the suspected attacker walking in. He was wearing a large jacket over a hooded sweat shirt and is seen walking toward an ATM machine, where he withdrew $200 from the victim's account, police said.