He said an internal investigation found that the four officers who have been cleared made some "bad decisions," but nothing was discovered of a criminal nature.
"I believe that the public should feel safe and confident in having these four officers back on the street," Pyle said.
Neighborhood Narcotics Unit officers Lt. John Coyle, Sgt. Michael Johnson, and detectives Ricardo Franco, Rafael Frausto, Barbara Lund, Sean McCarthy and Chris Smith and were placed on paid administrative leave in April amid allegations of corruption, mishandling evidence and systemic cover-ups. Cowley and Salmon were already on leave for the Willard incident.
Attorney Greg Skordas said his client, Frausto, is among the four who have been returned to duty.
"I think that he's pleased to be back to work," Skordas said. "He's back to work and he understands what happened and why."
Skordas said West Valley City has made some changes to department policy.
The four reinstated officers started back at various posts around the department on Wednesday, but will not return to the neighborhood narcotics unit, which remained disbanded as of Wednesday, Pyle said.
The narcotics squad was dissolved late last year amid allegations of systemic corruption, cover-up and "public perception" issues.
"Multiple investigations have been conducted both internally and by outside agencies into these allegations and, to this date, no corruption or cover-up accusations have been found or substantiated," the city said in a statement.
Pyle said the neighborhood narcotics unit will be restructured and relaunched at a later date, but investigating the nine officers' actions has been the immediate priority.
Aside from Skordas, none of the lawyers representing the officers immediately returned calls seeking comment.
Tony Yapias, director of Proyecto Latino de Utah, which has been critical of the actions of the unit, said he will "trust the department's judgment" in clearing them.
West Valley City Mayor Mike Winder praised the announcement.
"This is a bright day for the officers who have been cleared and are returning to duty," he said. "I look forward to when all of the investigations will be completed, and we will have resolution on all of the officers in question."
An FBI investigation and other outside investigations continued Wednesday, but Pyle said his understanding is "they have not found any evidence of widespread corruption or [anything that substantiates] these allegations of cover-up."
As a result of the ongoing issues, more than 125 federal and local cases linked to the unit have been dismissed by prosecutors.
Salt Lake County District Attorney Sim Gill said any cases filed by the narcotics unit officers will be looked at on "a case-by-case, officer-by-officer basis."
"We have to go back and take a look at what issues may be Brady-Giglio," Gill said, referring to the Supreme Court cases which require the defense to be informed about any issues involving an officer's credibility.
He said West Valley City's decision to reinstate officers is an administrative decision.
"We'll respect that," Gill said.
Pyle said each of the officers was independently investigated and reviewed. Other members of the unit still await a final decision in their cases, he said.
"We hold our officers to high standards and appropriate disciplinary actions have been imposed based on their varying degree of involvement and the severity of those violations," the city said in the statement. "Each employee has been afforded the same adjudication process and as the adjudications are completed and appropriate disciplinary actions are administered, the process will conclude."