SUNNYVALE — Police reported Monday that a Google engineer drowned in the bay off Moffett Field in December with no signs of foul play, but that their investigation and an autopsy could not determine exactly how she got into the water.

The Sunnyvale Department of Public Safety now considers the case closed on 23-year-old Chuchu Ma’s death.

“We did a very thorough investigation and the results of that showed there was no foul play involved,” Capt. Shawn Ahearn said.

A police news released added that “because intent cannot be unequivocally determined, the (Santa Clara County) Medical Examiner has ruled the manner of death to be undetermined.”

The partially dressed body Ma, of Mountain View, was spotted the morning of Dec. 9 by a cyclist along the Bay Trail, authorities said. Sunnyvale police declined to comment on her state of dress, referring to their statement that no foul play was determined in the death.

Hours after Ma’s body was discovered, Mountain View police received a missing persons report describing her.

Ma hailed from Spring, Texas, and was a 2016 graduate of the University of Texas-Austin with a degree in computer science — earning National Merit Scholar recognition — and a high school valedictorian, according to her LinkedIn page.

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In the wake of her death, Google released a statement saying “Chuchu was an excellent software engineer in our developer product team. We are devastated to learn of her passing, and our deepest condolences are with her family and friends.”