Update: Cathy Qiu, Honor Student Found Dead on Beach, was Smart and Loved Tennis, Friends Say

Updated at 12:50 a.m. Friday: 

Classmates of Cathy Qiu, the Albany High School student found dead on a San Mateo County beach Sunday, described her as highly intelligent, playful and always with a tennis racket.

"She was really smart...and she always had a tennis racket sticking out of her bag" said 17-year-old Albany High senior Treva Obbard, who shared an advanced math class with Qiu. Treva also spent the last four years in Spanish with Qiu, who was an honors student with a 4.35 grade point average.

Obbard said Qiu liked the television shows House and Smallville, and that she had a habit of punching holes in her notebook paper.

Many more students walking about during Albany High's open lunch hour said they didn't know Qiu personally. Some said they didn't know what to say about her death, given its mysterious nature.

Qiu's parent reported her missing on Sept. 27. Nearly a month later, her body washed up on a shore several counties away. Authorities are still awaiting toxicology and cause of death reports.

Updated at 5:15 p.m.:

Cathy Qiu could have run away from home nearly a month before being found dead on a San Mateo County shore Sunday.

The Richmond Police Department was investigating Qiu’s disappearance as a possible runaway case, said Richmond Police Lieutenant Bisa French. Richmond police received a report from Qiu's parents that the 16-year-old was missing on Sept. 27.

French said the death investigation has been turned over to the San Mateo County Sheriff’s office. The cause of death is still unknown and authorities are awaiting toxicology results.

Qiu was an Albany High School senior and resident of Richmond. She was an honor student with a 4.25 GPA and a member of the tennis team.

Updated at 4 p.m.: Message from the Albany Unified School District:

"Albany Unified School District reports with great sadness that according to San Mateo County Coroner’s Office, Albany High School 12th grade student Cathy Qiu passed away.

"The cause of death is pending investigation and awaiting toxicology results. No further information is available at this time.

"Qiu was reported missing by her parents on September 27, 2012, and Albany High School administrators have been in ongoing contact with the family since that time. Qiu attended Albany Unified School District on an inter-district transfer since the 5th grade. She was an honor student with a 4.25 GPA and member of tennis team.

"Albany High School students will be informed on Friday, October 26th when mental health personnel will be available on site."

Updated 3:41 p.m.:

Authorities identified a body found on a San Mateo County beach Sunday as 16-year-old Cathy Qiu of Richmond.

An Albany High School student identified Qiu as a fellow classmate after seeing a report of the washed up body on television Wednesday night, NBC Bay Area reported.

The San Mateo County Coroner's Office said Thursday that the body's dental records matched Qui's.

The Richmond teen was dressed in jeans, black boots and a red top, and had pink braces on her teeth when a couple walking along the beach discovered her body last weekend.

-Jamie White contributed to this article.

*More to come on this story.