Los Angeles police on Friday made an arrest in the death of a 30-year-old California woman after weeks of intense investigative work.

The Los Angeles Times reports Ezeoma Obioha, 31, was a business partner with Carrie Jean Melvin. Obioha contracted Melvin to do social media marketing work for his newly launched company, LAPD Lt. John Radke said. 

A dispute erupted when a check Obioha wrote Melvin bounced and she threatened to take him to court, authorities said. She never received hundreds of dollars that she was owed, police said.

Melvin, an aspiring actress and writer, and her boyfriend were strolling along McCadden Place shortly after 10 p.m. earlier this month. That is when Obioha allegedly walked up behind Melvin and shot her once in the head before jumping into the driver’s seat of a dark sedan. She was pronounced dead at the scene.

Police believed the murder was random at the time. There was no attempted robbery and Melvin’s boyfriend, whose name wasn’t released, was unharmed, police said.

Four days later, detectives had no leads in the hunt for the suspect.

"This is a very unusual crime," Los Angeles Polcie Department Detective John Swaggs told FoxNews.com.

Obioha was a one-time security guard who owned a clothing line, according to the newspaper. It’s unclear how the two crossed paths. His shop along Pico Boulevard sold urban-style T-shirts and hats.

Obioha also reportedly served on the LAPD’s community advisory board in the Wilshire district as the secretary to the Picfair Village Community Assn., covering the neighborhood near Pico Boulevard and Fairfax Avenue.

Melvin graduated from the University of California Santa Cruz in 2008 with a degree in arts, film and digital media.

"I am a connector of people within the entertainment industry," Melvin wrote on her LinkedIn page. "I, myself, model, act, produce, & write."

"I am CEO of World Media, otherwise known as W2W Media on twitter, specializes in online branding and social media marketing," she wrote. "We manage your social media campaigns, leaving you free to focus on your business and enjoy the life that you love."

“I’m thankful that he was apprehended and arrested, but we can’t celebrate,” her father, Bernie Melvin, told the Los Angeles Times. “This was a violent, senseless, meaningless act.”

On July 4, the day before she was killed, Melvin updated her Facebook page with a beaming photo of herself -- which friends were quick to compliment.

"'You are such a beautiful woman!'" wrote one friend.

"What more can one say -- lovely lady and I'm fortunate to know you," wrote another. 

Click for more from The Los Angeles Times.

Fox News’ Cristina Corbin contributed to this report.