When Belinda Lane buried her 24-year-old daughter a decade ago, she vowed to find those responsible for the gang-related firefight that stole her daughter’s life.

“I told her, ‘Baby girl, I promise you if it takes my last breath, I will get them; I promise you, you will have justice,'” Lane recalled in a recent interview with KABC.

“It could have taken a lifetime,” she added. “I never would have stopped.”

In the years since, Lane has been tracking one of the last suspects in her daughter’s death, in part by using social media — creating bogus accounts, then contacting the suspect and reporting his whereabouts to police.

Last Friday, that suspect, William “Jokes” Sotelo, was arrested in central Mexico, where he had fled following the crime, authorities told The Washington Post.

Sotelo, 28, is accused of driving the vehicle from which the bullets were fired that killed Lane’s daughter, Crystal Theobald, in 2006. He is being held without bail in Riverside, Calif., on charges of murder, attempted murder and discharging a firearm at an inhabited building.

Authorities said he is in custody because of Lane’s digital detective work.

“She was very instrumental, working on social media to help us identify where he might be,” Riverside Police Lt. Christian Dinco told The Post. “She provided important information that helped lead us to the capture of Sotelo.

“Without her help, he would likely still be outstanding right now.”

Sotelo’s public defender could not be immediately reached for comment.

Late at night on Feb. 24, 2006, Theobald was riding in her boyfriend’s Honda through Riverside, just outside Los Angeles, according to court documents.

She was sitting between her boyfriend and her brother, and they were following behind Theobald’s mother, who was in another car.

At an intersection, gang members were waiting in a Ford Expedition, according to court documents. The suspects later told authorities that they had been looking for rival gang members to “mess with,” according to court records, and authorities have since said that they may have mistaken Theobald’s car for one belonging to their rivals.

“Or,” said Dinco, the Riverside police lieutenant, “it could have been a cold-blooded attack.”

As the family’s two cars approached the Ford Expedition, a suspect climbed out of the vehicle and opened fire, according to the court documents.

Theobald’s boyfriend was shot in the stomach but survived.

Theobald was struck in the head and died from her injuries.

“I was just a mess; I was just so enraged, angry, sad, overwhelmed,” Lane recently told KABC. “I just didn’t even want to live. I just wanted to die.”

In the years that followed, almost a dozen people were accused in connection with the slaying and pleaded guilty to crimes ranging from witness intimidation to attempted murder, the Riverside Press-Enterprise reported in 2011.

Sotelo’s acquaintance, Julio Heredia, was named as the triggerman; in 2011, Heredia was convicted and sentenced to life behind bars, authorities said.

But Sotelo remained at-large.

And Lane went after him.

She told the Riverside Press-Enterprise several years ago that she started asking questions — and people in the neighborhood told her she might find answers on social media.

“You know, the streets talk,” she told the newspaper in 2011. “We were given information by various sources, so we created a couple of bogus profiles on MySpace.”

Lane said she created an account using the name “Rebecca,” then other using “Angel.”

She started sifting through sources until she found the man she wanted: Jokes Sotelo.

“hey what upp im new to myspace and i found ure myspacee,” she wrote to him, according to the Press-Enterprise. “u look hott we should chill sometime u would like me and my friends.”

“hey they call me jokes from varrio 5150×3 south side but my real name is William,” he replied.

Soon after, Lane went to police and gave them missing pieces they needed to pull Sotelo in for an interview, authorities told the Press-Enterprise at the time.

“He was the first one that gave us the clearest insight, and then other pieces began falling into place,” Det. Rick Wheeler told the newspaper. “He laid out quite a bit of the shooting to us.”

However, Wheeler said, authorities did not have enough evidence at the time to hold Sotelo.

Almost immediately, Sotelo disappeared.

It was June 5, 2006, when Lane momentarily gave up and confronted Sotelo with a message, according to the Press-Enterprise.

“Why did you … murder me?” she wrote.

“I blew my cover,” Lane told KABC of that moment. “I said, ‘If you claim you care about me so much, then why did you kill me? You don’t even know who you killed.'”

The following year, Sotelo, who was 17 at the time of the crime, was charged as an adult for his role in the slaying, according to reports.

But it would take years for him to be tracked down.

Lane said she kept up her social-media sleuthing and, in 2014, a tipster told her Sotelo was hiding out in Mexico, according to the Associated Press.

She alerted authorities, who were able to find him.

“I’m coming for you,” she says she told him. “You just hang tight, I’m on my way.”

Sotelo was captured in Mexico on May 6 and later handed over to Riverside police, according to booking records.

He has pleaded not guilty to all of the charges, according to the Riverside County District Attorney’s Office.

Lane said her daughter’s death tore her heart, but she remained committed to finding the accused killers.

“My sister gave me a mother-child statue and I wrote a message on the statue promising her that if it took my last breath I was going to get him and give her justice so she could rest in peace,” Lane told the Press-Enterprise this week. “Friday I was able to fulfill that promise and that’s everything I could ask for.”