The drive-by shooting of 7-year-old Jazmine Barnes in Texas last week galvanized celebrities, athletes, and civil rights advocates to call for justice for the little girl.

And it worked.

On Sunday, police acting on a tip delivered to activist Shaun King arrested alleged getaway driver Eric Black Jr., 20, and charged him with capital murder.

Authorities announced that they also have a second person in custody, who is believed to be the triggerman. They were still in the process of gathering more evidence against the unnamed man.

“We are still trying to verify information as this investigation is ongoing,” Harris County Sheriff Ed Gonzalez said, adding that Jazmine’s death appeared to be a case of mistaken identity and that the family was “innocent victims.”

The break in the case was a relief to Jazmine’s family, who are preparing for a public funeral service on Tuesday.

In an interview with The Daily Beast, Jazmine's mother, LaPorsha Washington, thanked everyone who helped in the investigation.

“Jazmine is gone, but now we have some answers to start the healing process. We will continue to fight for her and this is just the beginning,” she said.

Jazmine, still in her pajamas, was shot in the head Dec. 30 as her mother was driving to get coffee at around 7 a.m. with her three sisters.

Washington said that the assailant pulled up alongside them and opened fire without warning and for no apparent reason.

“When I heard what was going on, I went for my eldest daughter first because she was in the front seat with me. I couldn’t reach my other three babies in the back and just yelled at them to get down,” Washington said.

Washington, who was shot in the arm, said the suspect sped away, leaving the family in the middle of the road.

“One of my daughters realized first that Jaz wasn’t answering and said, ‘Mama, Jazmine’s not moving,’” Washington said.

Police originally said they were looking for a red pickup truck and released a sketch of a suspect, a white man wearing a hoodie.

An attorney for Jazmine’s family said earlier in the week that he believed that the shooting was racially motivated since the family is black and the gunman appeared to be white.

King, a writer and civil rights activist with a huge social media following, helped bring the manhunt for Jazmine’s killer to national attention, tweeting photos and videos of her and collecting reward money.

In an Instagram post on Sunday, he said he got a tip that Black and another African-American man were the culprits—which clashed with the family’s account of a white man in a red truck.

“Let me tell you the story of the red truck and how it came to be the focus of this investigation. Two men, in a completely different vehicle, pulled up and shot and killed Jazmine Barnes, shot her mother, and injured her sisters.

“Her mother and the girls never saw the shooter. They heard the shots, saw that Jazmine was shot in the head, that her mother was shot, and then looked up and saw this red truck with a white man driving it peeling off.

“THREE separate eyewitnesses, each credible, who also heard the shooting, also saw this truck speeding off. I spoke to each of them. They also assumed the white man driving it fired the shots. A brave man even followed the red truck in his own car and got a good look at him. A tow truck driver also saw the truck and got a look at him.

“In the meantime, the two men that actually shot and killed Jazmine drove off in a completely different direction through the neighborhood. They each later claimed that they thought they were shooting someone from a rival gang. Yes, they did it. No, they weren’t framed. It just took several days to solve it.”

Black, who appeared in Harris County court just before 5 a.m., was originally pulled over for not using his turn signal and arrested for marijuana possession, according to court documents.

While he was in custody, investigators learned he was one of the two men fingered by King’s tipster.

Black “admitted to taking part in the shooting,” Gonzalez said. According to court documents, he confessed that he was the getaway driver as the person in the passenger seat opened fire.

According to the affidavit read in court on Sunday, Black said the gun used in the shooting, a 9mm pistol, was still in his home and gave officers permission to search for it. The pistol found at Black's home was scientifically consistent with shell casings discovered at the scene.

Police confirmed to The Daily Beast that Black was driving a rental vehicle, though they declined to give more details. After the shooting, Black returned the vehicle and got a new rental, which he was driving at the time of his arrest on Saturday.

Gonzalez said the incident is a tragic case of “mistaken identity.”

“There were other individuals involved. Their target was likely someone else, but this family was fired upon,” the sheriff said.

Gonzalez said police would still like to speak to the owner of the red pickup “because perhaps they can shed some light on what happened that morning,” the sheriff said.

Underscoring the idea that the investigation is not yet complete, King late Sunday tweeted that he still has unanswered questions about the case, though he did not get specific.

Jazmine’s death—and possibly the prospect that the shooting might have been racially motivated—drew attention from a constellation of stars, including Gabrielle Union, Bruno Mars, and Olivia Wilde.

Houston Texans wide receiver Deandre Hopkins dedicated the paycheck from Saturday's playoff game to her family, and NBA great Shaquille O’Neal said he would pay for her funeral.

Hundreds of people showed up Saturday for a rally in her honor. Standing at a microphone, her mother wept as she thanked the crowd for its support.

“Only some of y’all mothers can feel where I’m coming from, the pain that I’m feeling,” Washington said. “Nobody else carried her for nine months, and she was so young... It’s not supposed to be like this.”