Police Officer Andrew Stinson and Sgt. Domenic Costello have been placed on paid administrative leave, and have had their badges and guns taken away from them in connection with a criminal probe into missing police union funds, Newtown Police Chief Michael Kehoe said Monday.

"I want to stress that they are not guilty of anything," Kehoe said of the pair. "We're conducting an investigation. We don't know where this investigation is going. Sometimes you have to make a call but you have to do that to maintain the integrity of the agency."

The investigation into alleged police union financial irregularities was officially announced on Friday. Unnamed members of the police union performed a preliminary review of its financial records dating back several years, and discovered there was money unaccounted for, including checks and cash, said Kehoe, who declined to comment on how much money was allegedly missing.

Stinson and Costello are "persons of interest" in the investigation, Kehoe said.

Costello had been out on vacation last week and Stinson had taken personal days for most of last week, but both came into the police department on Friday at Kehoe's request, the chief said, adding that he then suspended them from their policing duties and powers. Kehoe declined to comment on what else he discussed with the two.

The Danbury police department has been asked to come in and conduct an investigation into the matter.

"They are very well suited to do this kind of thing," Kehoe said of Danbury investigators. "They have experts in financial crimes on staff that have done that before."

While the investigation could take months, Kehoe said after talking to the Danbury police chief, he felt more confident that agency had sufficient resources to conduct a timely investigation. It was important to get answers as soon as possible, the chief said.

"This leaves almost a stain on this agency," Kehoe said.

Stinson, a nine-year police department veteran, was the president of the union and Costello, a seven-year department veteran, was the treasurer. Stinson has since resigned from the union presidency, Kehoe said.

Costello was promoted to a sergeant in 2009 and Stinson, who was the department's K-9 officer, had been a candidate for a sergeant position.

"They were very prominent officers in our agency who were involved in many things, key components of our agency," Kehoe said.

The two could not be reached for comment.

The union is expected to issue a press release. A message was left for the Waterbury lawyer representing the union. (Editor's note: Follow-up story here: 'That's Where That Check and Balance Broke Down')

The union includes every officer in the approximately 40-member police department except Kehoe and Capt. Joe Rios.

The revelations, uncovered last week, have rocked the department. Kehoe, who has been with the department for about 30 years, said he doesn't remember any similar scandal in the past.

"It's tough for everyone here," he said. "There's a lot of uncertainty that all of the officers face at this point."

Kehoe said he placed the officers on paid administrative leave and took away their police powers in order to maintain the integrity of the agency, and not as a disciplinary move. Additionally, Kehoe said that he does not believe that any of the cases the two officers were involved in have been placed in jeopardy.

"Our work product here is very scrutinized at all work levels," he said.