(CNN) -- A 23-year-old exchange student, attacked in her Toronto apartment while a friend in China watched via computer webcam, was found dead there hours later, police say.

Toronto Police on Monday identified the student as Qian (Necole) Liu of Beijing. She was talking early Friday morning to a male friend from home when a man allegedly knocked on her door, asking to use her phone, police said in a news release.

The online witness said he saw Liu and the unknown man struggle for a time before the attacker turned off her laptop, the news release said.

The friend in China then started a desperate bid to find out what happened, CNN-affiliate CTV reported.

Ten hours later, police arrived at the basement apartment to find Liu's body, naked from the waist down. Her laptop was missing.

"It was obvious that she had been dead for some period of time," Detective Sgt. Frank Skubic said in the news release.

The cause of the death is yet to be determined, the news release said. There were no obvious signs of sexual assault or severe physical trauma, and police are awaiting toxicology reports, it said.

Police are unsure whether Liu, an exchange student at York University, knew the man. The attacker was described as white, age 20 to 30, 6 feet tall, weighing 175 to 200 pounds, with a muscular build and medium-length brown hair, and wearing a blue crew-neck T-shirt.

With no suspects and no one in custody, police have been questioning neighbors, CTV reported. A cell phone found in the apartment is also undergoing forensic examination, police said.

York University President Mamdouh Shoukri released a statement saying, "Qian's death is a terrible tragedy and our entire community mourns the loss of a promising young student."

Liu's family is currently on their way to Canada from China, CTV reported.

A call to police seeking further comment was not immediately returned.

This is not the first time a crime has been captured by webcam. In the most notorious incident, Meleanie Hain of Lebanon, Pennsylvania was shot dead in 2009 while talking to a friend via webcam. The friend was looking away when he heard a shot and a scream, police said. Upon looking back at the screen, the friend saw Hain's husband firing a handgun at where his wife had been, they said. Police later found both Hain and her husband dead in their home.