By Tiffany Chan, WBZ-TV

FITCHBURG (CBS) — A Fitchburg man pleaded guilty to assault charges linked to the mother and siblings of Jeremiah Oliver. The five year-old boy was found dead in 2014. Fitchburg Police Chief Ernest Martineau is still looking for answers.

“Today was one small closure in one large book. And we’re going to continue moving forward the best we can in this case,” said Chief Martineau.

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No one’s been charged in the death of Jeremiah.

Alberto Sierra (Facebook)

Alberto Sierra entered a guilty plea in Worcester County Superior Court to three counts of assault and battery with a dangerous weapon, two counts of assault and battery, and two counts of endangerment of a child.

The little boy was last seen in 2013, but he wasn’t reported missing for several months. His body was found dumped in a suitcase off Interstate 90 in Sterling the following year in April. The death rattled many in the community.

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Jeremiah Oliver. (Photo credit: WBZ-TV)

“The name Jeremiah Oliver still comes up. It will never be forgotten. It’s a little young boy and what happened to him was horrific,” the chief added.

Alberto Sierra was sentenced to six to seven years in a state prison and three years probation for the assault charges. He had previously been charged with kidnapping and assaulting Jeremiah Oliver, and today, those charges were dropped.

Jeremiah’s mother, Elsa Oliver, is still facing charges. Her trial is set for August 30.

WBZ NewsRadio 1030’s Lana Jones reports

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