Interim head coach Brian Cabral said Sunday he had no idea of a timeline for the investigation.
In Joseph's absence, Hagan, who was hired in a defensive support staff position earlier this year, has found himself with more on-field duties in spring practices so far.
Hagan also said he didn't know any details about Joseph's situation.
"I don't know what's going on, to be quite honest with you," Hagan said. "But we all miss him and we look forward to him coming back. It's his secondary and I just don't want to screw it up while he's gone."
Hankwitz is in charge of the defensive backs overall, and Hagan has been working alone with the cornerbacks in certain drills, he said.
"I just watched the corners, just to make sure they were doing their technique, being in position," he said of Sunday's workout. "Just made sure they were being coached after every play. And I did some individual drills with them.
"I would take the corners and do some things with them. And (Hankwitz) would take the entire secondary and do some drills and foot work with them. Most of the time in the teaching phase of the practice, when we were talking zone with them, he had the safeties and the linebackers and then I had the corners."
While Hagan starred at quarterback for the Buffaloes from 1989-91, he played cornerback in the CFL for 5 1/2 years.
Cabral complimented Hagan on his work so far.
"It's been fun to watch him," Cabral said. "He's been impressive in his learning and his understanding. He really is a bright guy. He's helping us where we need him the most right now."
Part of what Hagan, under Hankwitz' watch, is doing is helping teach the new defensive system to the DBs.
"The philosophy is totally different," Hagan explained. "Last year, they played more man than zone. What we're doing, we're playing more zone with a little bit of man matchups; and we're playing some zone blitzes.
"We're putting guys in positions to not give up the big play."
When asked what has stood out about his new pupils, the CU cornerbacks, Hagan said, "They're fast and they're smart. It's due to coaching. VJ did a good job with them and they miss him."
Junior cornerback Vance Washington said the players weren't informed officially of Joseph's situation until Sunday, even though his absence made it obvious something was up. He echoed Hagan's wish for Joseph's return.
"We all love him," Washington said. "We've just been working hard doing football, and we miss him a whole bunch, and we want him back as soon as possible."
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