As some Massachusetts state troopers are pleading guilty to charges that they collected overtime pay for hours they did not work, the Boston Public Library is facing an overtime scandal of its own. WGBH investigative editor Paul Singer found out that janitors at the library had been leaving early on overnight shifts, but still getting paid time and a half for the full shift. Boston police are apparently investigating. Singer spoke with WGBH All Things Considered anchor Barbara Howard about what he found out. The following transcript has been edited for clarity.

Barbara Howard: What was the scope of the problem at the library?

Paul Singer: Well, there was about 30 janitors at the Central Library, and they racked up more than $300,000 in overtime last year. A lot of that was for cleaning up the library after-hours, after events. We don't know how much of that, but some portion of that is clear: they were not actually working.

I talked with one of those guys, Calogero Russo, a junior janitor who was fired in July. He explained to us how it worked:

For these wedding events, it's not the city money that pays us, it's the people that have the wedding. It's their money that pays us the overtime. If I had to cover a shift during the day, for the city, we would work the full eight hours, but when it was the wedding events, we wouldn't work the full eight hours.

Howard: And this was standard practice?

Singer: Apparently it was. At least that's what Russo says. It's been going on for years, and it was approved by senior managers of the library who oversaw the custodians.

Howard: But how did the police get involved?

Singer: Russo says his bosses wanted him fired because of his struggles with a heroin addiction. But in the disciplinary hearing in May, they accused him of falsifying his time sheets. And he responded by saying everybody else falsifies their time sheets on these overnight, overtime hours, and the bosses had all approved it. And that seems to have touched off this investigation.

Howard: Has anybody other than Russo been punished?

Singer: No custodians yet have been punished that we can tell. There are three senior managers who have been suspended. The library won't say what their status is at this moment, and we don't really know where the police investigation is headed. But Russo says at the moment he feels like it's unfair that he's the only one who's being pushed out.

I was fired for my addiction and then they brought up all those other little charges to justify firing me because they can't fire me for my addiction. I feel like it wasn't right and it was 30 of us doing it. Why am I the only one getting in trouble for this? Now they’re firing me and trying to not give me any unemployment benefits.

Singer: Russo says he wants some sense of fairness — he doesn't want anybody else fired, but he doesn't want to be singled out.

Howard: Now they were cleaning up after a wedding, but what if they were done early? Were they expected to stay the full eight hours if they were done in three or four?

Singer: Well they were billing for the full eight hours. They were filling out their time sheets saying they were there for the full eight hours. So I think part of the question is, maybe the library should change its practices, so you just pay some kind of flat cleaning fee and they can go home when they're done. When they finish, they finish. But the way it currently works, they fill out a city time sheet that says I worked all night, even when they didn't.

Howard: Thanks for joining us, Paul.

Singer: Thanks, Barbara.

Howard: That's WGBH investigative editor Paul Singer, who is looking into janitors at the Boston Public Library getting paid time and a half for overnight shifts that they left early. WGBH News did reach out to officials with the library for comment. They said that they could not discuss an ongoing investigation. This is WGBH's All Things Considered.