Amazon is resisting an effort by prosecutors in the US to obtain potential recordings from a murder suspect's Amazon Echo smart speaker.
It said authorities have not established that their investigation is more important than a customer's privacy rights.
The issue comes in the investigation into the death of Victor Collins, who was found floating face up in a hot tub at a friend's home in Bentonville, Arkansas, in November 2015.
The friend, James Andrew Bates, has pleaded not guilty to first degree murder.
Benton County prosecutors asked a court to force Amazon to provide data that Bates's Echo may have collected.
Echo devices "listen" for a user's voice and respond to commands.
In a response filed on Friday, Amazon said prosecutors had not established the need for the company to violate its customers' constitutional rights.
The firm said prosecutors must prove the information is not available elsewhere.
Amazon also wants the court to review the recordings before turning them over to prosecutors to ensure they are actually relevant to the case.
"Given the important First Amendment and privacy implications at stake, the warrant should be quashed unless the Court finds that the State has met its heightened burden for compelled production of such materials," Amazon said in the court documents.
The company had previously spoken about prosecutors' request for the information in more general terms, but this is Amazon's first formal legal response to the subpoena for audio recordings and transcripts from the night of Mr Collins's death.
"Amazon will not release customer information without a valid and binding legal demand properly served on us. Amazon objects to overbroad or otherwise inappropriate demands as a matter of course," the company said in a statement.