SAN FRANCISCO (CBS SF) — San Francisco police have boosted the reward for information to $250,000 in the 2016 homicide of Nicole Fitts and the search for her missing toddler Arianna Fitts.

The body of Nicole Fitts was found buried in the city’s McLaren Park on April 8, 2016. She had been reported missing by her famiily members along with her two-and-a-half-year-old daughter Arianna. Police said investigators determined the child was in the care of her babysitter and her husband at the time of her disappearance, and that Fitts was lured to meet the babysitter during the time of her disappearance.

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“We know there’s an explanation for what happened,” said San Francisco Police Acting Commander of investigations James Aherne. “This is a tragic situation for everyone involved and we know people associated with this matter want to be heard. We want to hear from you. We will listen to you. We continue to have an open mind and are considering all possibilities.”

Arianna Fitts at the time of her 2016 disappearance and in an image prorgression to age 8. (San Francisco Police Department)

FBI Assistant Special Agent in Charge Scott Shelby said in the last few months investigators have developed many new leads, new people come forward with information, and additional evidence recovered.

“Additionally, there have been significant advances both in digital and biological forensic evidence that is allowing us to see much more than what we knew six years ago,” said Shelby.

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Shelby added that investigators can’t reveal everything they know about the case and they hope more people will jostle their memory and come forward.

“We believe there are multiple people with direct knowledge of this case who have not fully cooperated with law enforcement,” said Shelby. “We believe there’s an even a larger circle of people with indirect knowledge of what happened. Perhaps you heard of something or thought of something that night. Perhaps you know more of Nicole’s last movements or have heard some information about Arianna’s whereabouts. We are asking you please to come forward to law enforcement.”

Arianna Fitts, missing after her mother was found killed in San Francisco’s McLaren Park on April 8, 2016 (San Francisco Police Department).

Police on Friday released a new age-progression image of what Arianna might look like. Last year, the FBI released an age-progressed sketch hoping to generate leads as to where the little girl may be.

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Police have previously offered a $100,000 reward for information leading to the arrest and conviction of those responsible for the crimes.

Source: sanfrancisco.cbslocal.com.