Google-owned Nest went to great lengths to conceal its acquisition of Seattle health monitoring start-up Senosis in order to keep its interest in digital health a secret, new records obtained by GeekWire show.

While GeekWire had previously reported that Google had bought the start-up in the summer of 2017, the records confirm that it was actually Alphabet's home automation business Nest that wished to integrate Senosis's technology. However, the company told those involved in the deal that they couldn't mention Nest or publicize the sale.

"It turns out Nest is much more secretive than the rest of Google or Alphabet," Senosis co-founder Shwetak Patel wrote to the vice president of University of Washington's innovation hub in June 2017. "They seem to be particularly sensitive in this situation since they don't want people to know they are getting into a whole new line of business, digital health, until they are ready to publicly announce."

Senosis Health spun out of the University of Washington, which enabled GeekWire to make public records requests related to its sale.

Emails also show that Google's corporate counsel instructed the team to use "Google" instead of "Nest" on outside forms and in internal discussions to prevent speculation around a Nest health product.

When Nest bought Senosis, which turns smartphones into health monitoring devices, it was still an independent business unit of Google parent company Alphabet. Earlier this year, it rolled back into Google and combined with the Google Home team, which creates smart speakers and other living room products.

It's unclear how these organizational changes could affect its health plans.

Nest has recently been in talks with senior living homes and has explored new products to help seniors live independently as long as possible, CNBC has previously reported.

Nest declined to comment.

Read the rest of the GeekWire report here.

Know anything about Nest's health plans? Reach out to the author at jillian.donfro@nbcuni.com or via encrypted chat app Signal at 415.412.9788.