SACRAMENTO (CBS13) — The man accused of brutally beating and killing a 13-year-old girl was sentenced to 26 years to life behind bars.

The senseless tragedy took place in the baseball dugout of the Rosemont Community Park. Police found Jessica Funk-Haslam’s body, but no killer. Her mother was left grief stricken. She said that night in March 2013, the two argued and the teen ran.

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Detectives questioned multiple people, but hit a dead end.

The prosecution believes those answers came a year and a half after the teen’s death from DNA on cigarette butts. It matched the 13-year-old and Ryan Roberts, who was 21.

“I’ve never given up hope in the beginning and not now,” said Jessica’s mother Tara Haslam a year after the murder.

Now she’s convinced the right person is behind bars and released this statement:

“I believe she wouldn’t give him what he wanted [sex] so he killed her.”

But another mother said there’s no way.

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“Her belt was slightly to the side, It wasn’t perfectly centered with her naval, so the prosecution tried to say it was twisted and evidence of sexual attack. Nothing,” said Tammy Roberts, Ryan’s mother. “There was no sexual attack and that was not the motive,”

Roberts believes there were a number of errors concerning evidence in her son’s case leading to his conviction. She said son may have been smoking cigarettes with Jessica, but said he didn’t kill her.

“They had the DNA. They had the victim’s DNA on it, they said that’s our killer. They were blinded to everything else,” said Roberts’ mom.

However, things didn’t look good for Ryan either. He lied and said he was never in the park and was once accused of attacking his ex-wife, although investigators said there wasn’t enough evidence to charge him.

Either way, the jury was convinced it was Ryan Roberts and sentenced him to 26 years to life behind bars.

“Are we going to have to be one of those families that has to wait 20 years for the truth comes out? Is my son going to lose half of his life before the truth comes out?” said Roberts.

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His case is on appeal.