(CNN)About a week after Tamir Rice's mother and her legal team publicly asked how long it would take to finish the investigation into her son's death, the Cuyahoga County sheriff said Tuesday -- 171 days after the 12-year-old was shot -- that his department is almost there.

Sheriff Clifford Pinkney provided what he said was a timeline of the investigation, which his department took over in December before beginning its investigation "in earnest" in mid-February. He told reporters that he and his investigators had resolved to leave "zero stones unturned" when the investigation is handed to prosecutors.

The Gray family's legal team criticized what it said was the torpid pace of the investigation and said the drawn-out process is fueling suspicions that a coverup is in the works.

"It's been now spanning three seasons, going up on 6 months, and sometimes justice requires just a little more diligence," family attorney Walter Madison said. "What can be taking so long when you have the entire event there on video? A crime fighter's dream."

Pinkney said his investigative team has reviewed thousands of pages of documents, interviewed numerous witnesses and watched "any and all" surveillance video of the November 22 incident in which Cleveland police Officer Timothy Loehmann fatally shot the boy in front of a recreation center.

Still, there are witnesses to be interviewed and forensic evidence to be collected, Pinkney said.

"The majority of our work is complete," he said. "We have been tirelessly working on this investigation."
http://www.cnn.com/2015/05/12/us/cleveland-tamir-rice-investigation...