ARLINGTON -- An arrest was made in the death of an Arlington mother who was killed trying to earn money for groceries and her little girl's Christmas presents.

Mario Hernan Lopez Gamez, 33, was located in Houston on Saturday.

Arlington police say April VanCleave was trying to sell jewelry through the app "5Miles" to "complete an online exchange" on Dec. 15, 2016, so she could have money for Christmas. She agreed to meet her buyer near Target on South Cooper Street, but they never showed up.

Instead, detectives say two men, captured on surveillance video, followed VanCleave and her husband back to their apartment. When her husband dropped her off, an arrest affidavit says Gamez and an unknown suspect robbed, shot and killed VanCleave in the parking lot.

The suspects stole her purse and jewelry.

On Sunday Mark VanCleave said he hopes the second suspect in his sister's murder will turn himself in.

"Now there’s just a little bit of relief for my family,” VanCleave said. "These guys left an old couple, my parents, with a little girl to raise that cries herself to sleep every night."

Marissa Mathews saw the surveillance video on Facebook after VanCleave’s murder.

“I knew immediately it was him,” Mathews said.

The Mansfield mother of two says the face and the way the man walked in the video was frighteningly familiar. Mathews says she was looking to sell a piece of jewelry in late November and thought she found a prospective buyer through the resale app “Offer Up.” When she met him on the street outside her home, she says he grabbed the jewelry and her phone and hit the gas with her arm still inside the pickup.

“The only thing I could think of first was, I could die,” Mathews said.

She says she was wearing a long sleeve jacket and managed to unzip it, which freed herself from the truck as it sped away.

In a five-page arrest affidavit released Sunday, detectives say they were able to link Gamez to both accounts on Offer Up and 5 Miles to a phone number that had a high concentration of GPS activity at a north Dallas apartment complex. The affidavit says apartment management positively ID'd one of their tenants as one of the men from the Target surveillance video.

Detectives with the U.S. Marshals North Texas Task Force coordinated with the U.S. Marshals Gulf Coast Fugitive Task Force to make the arrest on Saturday.

Mathews said Sunday evening she knows she's lucky to share her story because VanCleave can't.

“Hopefully this was the last time he was able to do something like this and pull it off, but more than likely there’s other victims out there,” Mathews said.

Can't see the video above? Go here.