ID=14933053DALLAS — Freddie Washington was possibly the last person to see 5-year-old Katherine Gonzalez alive besides her killer.

He saw her with Katherine's 17-year-old cousin, Angel Sanches, Sunday morning as they walked a dog.

"First thing I asked was, 'Is that your dog?'" Washington said. "And he said, 'No, my prima's dog,' which means my cousin's. And she said, 'Oh, my dog? Do you like my dog?' And I said, 'Yes, very pretty.'"

Washington said Katherine and her cousin were standing in front of the apartment where police later found her body. Monday, police announced the arrest of Sanches in the strangulation death of the young girl.

REPORT: DPD: Cousin arrested in strangulation death of 5-year-old girl

"When I walked down this way and they were behind me, he kept telling her 'Come on, come on,'" Washington said.

Less than an hour later, Washington said he heard yelling.

"A lot of men were running around with her picture on a cellphone and said, 'Have you seen her?' he said. "And I knew I had just seen her."

Katherine's aunt called 911 and reported her missing. While her uncle was supposed to be watching her, he let her go outside to play. There was a frantic search in which police, loved ones and neighbors searched the area.

"People even went so far so to allow officers into homes and cars to search for this child," said Maj. Rob Sherwin.

The little girl was found hours later inside a vacant apartment next door to Sanches' unit.

Washington said relatives at the scene were screaming at Sanches to tell police what happened to the child.

"He was like, 'I don't know; I was asleep,'" Washington said. "And I said, 'That's a lie. Where is the child? Where is she?'"

Police say after talking to Sanches until 3 a.m. Monday, he was arrested and charged with capital murder.

Sanches is being held on an immigration hold. They believe he entered the country illegally six months to a year ago.