Autopsy shows Google engineer drowned, but why she went into the water is a mystery

Chuchu Ma's nude body was found in the Bay on Dec. 7.
Chuchu Ma's nude body was found in the Bay on Dec. 7.

Daily Post Staff Writer

Chuchu Ma talked about “going into the water” on a disoriented 911 call that she made the day before her naked body was found floating in a drainage ditch of the San Francisco Bay last December, according to emails and autopsy documents obtained by the Post.

Santa Clara County Medical Examiner Joseph O’Hara signed off on Ma’s autopsy report on March 28, declaring that the 23-year-old Google engineer had drowned to death, but leaving her manner of death as undetermined. He and investigators were still puzzled over the circumstances surrounding her death as recently as last week.

Sunnyvale police detectives have ruled out foul play, but believe Ma’s death was more likely an accident than a suicide, according to an email from Santa Clara County Coroner Investigator Andrea Whelan.

“I do not see how this is an accident…why would she completely undress and jump in the water?” O’Hara asked in an email to Whelan on March 26. “Unless they mean that she was psychotic and drowned accidentally while hallucinating.”

The psychosis theory appears to have been the most conclusive one that police could come up with. “The police think that the decedent may have been psychotic and drowned accidentally, however her comments on the 911 tape about ‘going into the water’ cannot be ignored,” Whelan wrote back to O’Hara on March 28. “The police are just not thinking this is a clear ‘suicide.’”

Sunnyvale Department of Public Safety Capt. Shawn Ahearn told the Post yesterday that his department had not yet received Ma’s autopsy report, but would make a “full release” on the investigation once it had.

Ma was making plans for the future as late as the day before she was found dead, according to an email to investigators from her mother, Li Chen.

She booked a January plane ticket from San Francisco to Munich, Germany on Dec. 6, according to a Jan. 9 email from Chen to Whelan and Sunnyvale police Detective Matt Hutchison.

Ma was also planning a January trip to Austin, Texas, where she graduated from the University of Texas in 2016, Chen said. Her 24-year-old boyfriend, Isaac Smith, is a third-year math Ph.D. student there.

Investigators did not find evidence of suicidal ideations or threats in Ma’s medical records, though they were still searching her medical records the day that O’Hara signed off on her cause and manner of death, according to emails.

Injuries consistent with drowning

Excess water in Ma’s brain and lungs, along with mild scrapes to her forehead and body, appeared consistent with a drowning, O’Hara wrote.

She had no other injuries and the only drug in her system was caffeine. Her blood sugar was slightly elevated and she had chronic pancreatitis, but this didn’t seem to be relevant to her death, O’Hara wrote. There was no indication of a sexual assault.

In a Jan. 10 email to Ma’s mother, Li Chen, Whelan asked if Ma had ever suffered from narcolepsy or sleepwalking, but Chen said she wasn’t aware of anything like that.

Chen suggested that Ma may have fallen off her bicycle and dropped a medical device she was wearing for a glucose study in the water and drowned while trying to retrieve it.

“She fell off her bike several times before,” Chen wrote.

O’Hara noted that, “according to reports,” she was witnessed entering the water on Dec. 6 while using her cellphone, but didn’t say who had seen this happen.

Sounded confused in a 911 call

Ma had been behaving erratically “according to her companion” and a 911 call recording in which she sounded “confused and disoriented,” O’Hara wrote.

Smith, who was visiting Ma at the time of her death, reported her missing to the Mountain View police at 2:25 p.m. on Dec. 7, four hours after a passing bicyclist found her body along the San Francisco Bay Trail, north of the Golf Club at Moffett Field.

Smith said he hadn’t seen Ma since 10:30 a.m. the day before.

The county medical examiner’s office took almost four months to release Ma’s autopsy report. The Sunnyvale Department of Public Safety has remained tight-lipped on the investigation while awaiting the finalized autopsy.

Six days after Ma was found dead, Ahearn said there was “no danger to the public” in the area where Ma was found. She lived in an apartment in Mountain View and had worked for Google since July 2016 after graduating with a bachelor’s degree in computer science.

Friends and family have remembered her in online tributes as a passionate and talented engineer and musician as well as an adventurous social butterfly who brought people together over food, Nintendo games and outdoor adventures.


  1. Report could have been better to mention where she mught have left rest of the clothing. She left home with the same clothing as she found worn dead, or was possible CCTV record found along the road she approached. One more thing, the report want clear that the time she called 911 to tell her intention to into water is actually, or probably the same time when her body was put into water.

  2. Where were Miss Ma’s Clothing at the time she was found? How is a scrape on the forehead consistent with drowning. Who and where is the witness that witnessed Miss Ma entering the water? Why no name? Usually a witness has no problem with speaking to the media. Why did it take almost 5 months to report this? I pray Miss Ma is in a peaceful place and however this happened gets resolved. It seems many are not being forthright with info and as a resident and trail user and human it is very disturbing

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