The photos appeared on Jennifer Streit-Spears' Facebook page Sunday morning, just as many of her friends and family members were preparing to go to church.

Normally, the 43-year-old posted cheery pictures of cuddly animals, inspirational tattoos, Christmas trees or smiling family portraits.

These photos, however, were anything but cheery.

They were horrific.

In the hazy images posted Sunday morning, Streit-Spears appeared to be dead. Her neck was slashed and she was covered in blood.

Appearing alongside her and apparently holding the camera was a man with a wild beard and unruly hair. Some of Streit-Spears' friends recognized him as her boyfriend, Kenneth Alan Amyx. He, too, was covered in gore.

"Please pray for us," read a message posted with the photos at 9:41 a.m.

"Love you all," said another message a minute later.

At 10:03 a.m., Streit-Spears' mother called 911 and told dispatchers that her daughter and Amyx were "going to kill each other," according to an affidavit obtained by NBC5.

Police raced to Streit-Spears' apartment near a golf course in Plano, Texas. When they finally burst inside, they found the couple naked in a pool of blood in the bedroom. Amyx was lying on top of Streit-Spears. Both initially appeared to be dead, according to the affidavit.

Then cops heard Amyx make a noise.

When they tried to help him, they found a knife in his right hand. And despite an eight-centimeter (about 3 inch) wound to his own neck, Amyx quickly confessed, according to the affidavit.

While drinking, the couple had decided to kill themselves, he told investigators. But Streit-Spears had "chickened out," so Amyx had to "finish her off," he told police.

Collin County prosecutors have charged Amyx with murder, according to the Associated Press.

The brutal crime has shocked those who knew Streit-Spears, particularly those who learned of her death via the vivid Facebook photos.

But the incident has also stirred deep anger towards both her alleged killer and the social media website.

Amyx had two outstanding arrest warrants in neighboring counties over alleged sexual offenses involving children, leading some critics to ask why he was free in the first place.

Facebook, meanwhile, has come under attack for leaving up the gruesome photos for roughly 36 hours, despite demands from Streit-Spears' grieving family members.

The social media site has defended itself, however, saying it initially thought the photos were a call for help from the victim.

Amyx and Streit-Spears had been friends since childhood, he told investigators. They began dating around four months ago, after other relationships had fallen apart.

From the beginning, however, a shadow hung over them.

In February, a grand jury in Rockwall County indicted Amyx on a first-degree felony charge of continuous sexual abuse of a child younger than 14, according to the Dallas Morning News. Amyx had admitted to "several acts of aggravated sexual assault" against a 13-year-old girl in Rockwall and Dallas counties.

It is unclear why Amyx was not arrested then. Court records show arrest warrants in both counties.

In Plano, Amyx and Streit-Spears plotted a Romeo and Juliet-style escape. First, they planned to beat the charges against Amyx by running away together. Then they decided to commit suicide instead, according to the affidavit.

They discussed the idea for a few months. Then, on Sunday morning, while drinking, they "agreed to stab one another until they died," according to the affidavit.

They each had a knife.

"Amyx stated that he cut the back of her neck first and then they took turns cutting one another," the affidavit says. At one point, Streit-Spears allegedly said she was cold and asked Amyx to stab her harder.

"He then said he came down hard ('like cutting tomatoes') and when he pulled the knife out blood came all over the place," according to the affidavit.

When it came time for Streit-Spears to stab Amyx, however, she allegedly said she was too weak.

"Amyx said that he grabbed her hand (that had the knife) and cut himself hard," according to the affidavit. "Amyx said that he then posted photos of both of them (wounded) on Facebook and then [texted] Streit-Spears['s] mother the same picture."

When her mother received the text, she called the police. Many friends, meanwhile, saw the shocking photos on Facebook.

"We were looking at Facebook and saw these very strange pictures," Fran Stamey told the local CBS station.

"The pictures were not clear although they were extremely scary," Stamey said. "I just started to reach out to our mutual friends to see if they've anybody knew anything."

Stamey and several dozen other friends notified Facebook of the disturbing photos, according to CBS, but the photos stayed up.

Even after Streit-Spears' family learned that Jennifer had been killed, they could not get the pictures of her dead body off Facebook.

"I did ask them to remove it several times," Jennifer's sister told the Daily Dot on Monday, when the photos remained up. "They told me I could block Jennifer if I didn't like what she posted and gave me other similar options."

On Monday night, Facebook finally removed them.

"We reviewed the post you reported for promoting graphic violence," Facebook posted at 8:08 p.m., according to CBS. "Since it violated our Community Standards, we removed it. Thanks for your report. We let Jennifer Streit-Spears know that their post has been removed, but not who reported it."

By that point, Streit-Spears had been dead for nearly 36 hours.

Facebook has defended its decision to leave the photos up for that long, saying it initially thought they were a call for help from the victim rather than the killer, according to the New York Daily News.

"Facebook has long been a place where people share their experiences and raise awareness about important issues," a Facebook spokesperson told the newspaper. "Sometimes, those experiences and issues involve violence and graphic images of public interest or concern."

The Texas incident is not the first time a man has allegedly killed his female partner, then posted a photo of her dead body to Facebook.

In 2013, a South Miami man shot his wife before uploading a photo of her corpse to the website. Derek Medina argued in court that he killed Jennifer Alfonso in self-defense after she attacked him with a knife, but that claim was undercut by his post-mortem Facebook post. In November, the "Facebook killer" was convicted of second-degree murder and sentenced to life in prison.

According to the affidavit, Amyx claimed he was merely carrying through with the suicide pact after Streit-Spears "chickened out."

It's unclear if he will pursue that line of defense in court.

His attorney, Keith Gore, told the New York Times on Tuesday night that some aspects of the case had not yet come to light but did not elaborate.

"A motion to reduce bond will be filed with the courts in the near future," Gore told the Morning News. "Our thoughts are with the family and friends of Jennifer Streit-Spears."

Those family and friends, however, are still shell shocked by the social media slaying.

"I'm angry, upset, frustrated," Stamey, who spotted her friend's corpse on Facebook, told CBS. "What is the world coming to. . . not only committing the crime but posting pictures?

"It's hard to think that somebody would just do something like that and have the guts to post [it]."