(CNN) Police have arrested a suspect in connection with the death of 7-year-old Jazmine Barnes, and they're giving credit to a tip from social activist and writer Shaun King.

The arrest of Eric Black Jr. -- who said he was driving the vehicle used in the shooting -- came as a result of a tip King received and sent to Harris County Sheriff Ed Gonzalez, the sheriff said Sunday.

"He became a target in our investigation based on a tip that initially went to journalist and activist Shaun King," Gonzalez told reporters. "Mr. King then passed that tip to me personally."

Two days after Jazmine's death, King turned to his legion of Twitter followers to enlist their help in finding her killer and offered a reward of $25,000 for information. S. Lee Merritt, an attorney advising Jazmine's family, also joined the cause. The reward eventually climbed to $100,000.

On Wednesday evening King had tweeted he had combed through hundreds of tips. "Mostly garbage," he said. "All well meaning. 3-4 helpful. Working with the family and local authorities. Some promising leads, but not nearly enough."

Shaun King

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