Yubo explained and why it has emerged as part of Uvalde shooting probe

Described by its inventors as a "social live-streaming platform" that allows its mostly teenage users to make friends worldwide, join communities and even find a date, Yubo has emerged as part of the investigation into the school shooting in Uvalde, Texas, because the suspect sent messages through the app, investigators and users told ABC News.

Launched in 2015 by a French company, Yubo has quickly become known as a go-to site for mostly "Gen Z" users to meet, make new friends and join online communities. In 2019, Seventeen magazine also listed the site as among the seven best dating apps for teenagers.

"Yubo is a social app for Gen Z that allows them to connect and interact with people all over the world through live streaming," a spokesperson for the platform said in a statement to ABC News. "Yubo gives this generation a space to socialize through one-to-few audio and video conversations, games and chat, and empowers its 60 million users to connect safely and without the pressure of likes or follows."

Yubo even has separate areas of its app reserved for teenagers. Users who join and say they are between the ages of 13 to 17 are put into different "communities" and supposedly can't interact with other users who say they are over 18, according to the platform.

Yubo appears to work like a blend of livestreaming social apps like Clubhouse and Twitch, mixed with adult social media and dating apps like Tinder that allow users to swipe through individual profiles. The app lets users make friends, send direct messages, swipe between users, and join livestreams, either video or audio.

But multiple users told ABC News that they believe accused Uvalde mass shooter Salvador Ramos had a more sinister use for the platform.

Two users claimed Ramos allegedly committed animal abuse and displayed videos of the cruelty on Yubo.

An individual who claimed to have known the accused gunman through the social media platform told ABC News that Ramos turned on his video last week on the platform and showed himself with guns and allegedly made statements, including "wait till tomorrow."

"No one took him seriously," another user told ABC News.

A law enforcement source said detectives probing the Uvalde mass shooting are aware of a Yubo account believed to have belonged to the accused gunman but can't definitively confirm the account belongs to the suspect. ABC News has not independently verified that the alleged account belonged to the accused shooter.

"Our thoughts and deepest sympathies are with the families of the victims of the tragic shooting in Uvalde, Texas," the Yubo spokesperson said. "Due to privacy regulations, we are not able to release specific user information outside of direct requests from law enforcement."

Just days after his 18th birthday, Ramos allegedly killed 19 students, most just 10 years old, and two faculty members Tuesday at Robb Elementary School in the small rural town west of San Antonio. The suspect was fatally shot by law enforcement officers.

Moments before carrying out the deadly attack, the accused gunman allegedly sent a string of messages to a young girl he met on Yubo, detailing that he had shot his grandmother and was heading to the school for his next target, according to messages reviewed by ABC News.

The messages allegedly show the accused gunman texted with a 15-year-old girl in Germany. He allegedly described an argument he had with his grandmother over a phone bill.

"She's on the phone with AT&T," Ramos allegedly wrote at 11:06 a.m. on Tuesday, about a half-hour before the attack at the school, apparently referring to his grandmother with a derogatory term. In another message, he allegedly said, "Ima do something to her rn (right now)."

Moments later, he allegedly wrote, "I shot my grandmother in the head." He then allegedly wrote, "ima go shoot up a elementary school rn."

The young girl who allegedly received messages from the Texas gunman moments before his rampage told ABC News Thursday that she has been asking herself "what if I could change the outcome" since seeing the news that her friend had committed the school massacre.

The girl, who asked to be referred to as "Cece," said, "Ever since May 24th I have been guilt tripping myself, what if I could change the outcome, what if I could change his mind to not do this. I was too dumb to realize why he bought two rifles on his birthday, May 16th, and ordered a package full with ammunition, not knowing what he was going to do with it."

Cece said she met Ramos on May 9 on Yubo, where they would "join each others live" streams.

While in a previous interview with the New York Times Cece said she read the messages from the gunman "as soon as he sent them," which would have been minutes before the shooting, she now tells ABC News she "misspoke" and that she only saw them "hours later."

Cece, who said she and Ramos exchanged cellphone numbers and spoke regularly, claimed there were other warning signs in hindsight, including that the suspected gunman would ask others on Yubo "if they would want to be famous on the news."

At a news conference on Wednesday, Texas Gov. Greg Abbott referenced similar messages the gunman sent just prior to the school rampage, but misrepresented them as "Facebook posts" when they were instead private "one-to-one text messages," according to a spokesperson for Meta, the parent company of Facebook.