Police in Florida believe recordings from a murder suspect's Amazon Echo may contain crucial information as they investigate an alleged argument at the man's home that ended in his girlfriend's death.

Adam Reechard Crespo, 43, is charged with murder in connection to the July death of Silvia Galva, who died after suffering a stab wound to the chest.

The Broward County Sheriff's Office believes Crespo's Echo - a smart speaker that connects to the Amazon voice-activated personal assistant Alexa - may have been a witness to the crime and obtained search warrants for all the device's recordings.

Hallandale Beach Police Department spokesman Sgt Pedro Abut told the Sun-Sentinel that the department has received the recordings and is "in the process of analysing the information that was sent to us".

The police department did not immediately return NBC News' request for comment on Saturday.


Image: Investigators have obtained search warrants for all of the Amazon Echo's recordings

Crespo's attorney, Christopher O'Toole, said he believes the recordings will exonerate his client.

"We want to hear these recordings as well," O'Toole said in an interview with NBC's Weekend Today show. "I believe in my client's innocence 100%. And I think that these recordings are only going to help us."

An Amazon spokesperson said in a statement that the company "does not disclose customer information in response to government demands unless we're required to do so to comply with a legally valid and binding order".

The statement added: "Amazon objects to overbroad or otherwise inappropriate demands as a matter of course."

According to Amazon.com, in order for a device to start recording, the user has to rouse the device by saying the wake word "Alexa". The owner can change the wake word to Amazon, computer or Echo.

"Only then does the device begin recording and sending your request to Amazon's secure cloud," the website states. "You'll always know when Alexa is recording and sending your request to Amazon's secure cloud because a blue light indicator will appear or an audio tone will sound on your Echo device."

The device's owner has the option to delete recordings.

Image: Recordings from Amazon's Echo may hold key evidence in the case. Pic: Sylvia Michelle/Facebook

Crespo, 43, told police that on 12 July that he and Galva got into an argument in the bedroom of his home in Hallandale Beach, about 12 miles south of Fort Lauderdale, after they had been drinking. He said he grabbed her by the ankles to pull her off the bed, according to a probable cause affidavit.

At the foot of the bed was a spear with a 12-inch double-sided metal blade. Crespo said that, as he pulled Galva, she grabbed onto the wooden shaft of the spear and he turned away from her.

"While he was still pulling her from the bed he heard a snap," according to the affidavit. "The defendant turned around and discovered... the blade had penetrated the victim's chest."

Crespo told authorities he pulled the blade out "hoping it was not too bad" and then told a friend at the home to call 911.

Staff at the hospital Galva was taken to said the blade pierced her sternum "at an angle".

Authorities wrote in the affidavit: "Based on the information received the actions of the defendant caused the victim to grab the spear to keep herself on the bed.

"The force used by the defendant to remove the victim caused the shaft to break and in an unknown way caused the blade to pierce the victim, which caused the loss of life."

This is not the first time Alexa recordings have been sought for a murder investigation. In 2015, prosecutors in Arkansas asked Amazon to hand over recordings from an Echo device at the home of James Bates, who was charged in the death of his friend Victor Collins.

Collins was found dead in Bates' hot tub in November 2015, the Arkansas Democrat-Gazette reported. Court documents obtained by the outlet said Collins died from strangulation with drowning as a secondary cause.

Bates said he was innocent and was in bed when Collins and another friend were in his hot tub. Bates said he called the police when he woke up the next morning and found Collins' body, the document states.

Amazon turned over the recordings only after Bates' legal team consented, according to the Democrat-Gazette.

Prosecutors said the recordings contained no evidence, and a judge eventually dismissed charges against Bates.