Wales boss Warren Gatland has revealed his sense of shock after Rob Howley was sent home from the World Cup for an alleged breach of World Rugby's betting and anti-corruption regulations.
The Wales head coach said his assistant coach was left "devastated" by the allegations.
Welsh Rugby Union chief executive Martyn Phillips revealed that he was first made aware of matters last Wednesday, which was Wales' World Cup departure day to Japan.
The WRU said that 48-year-old former Wales captain Howley had returned to Wales to assist with an investigation in relation to a potential breach of World Rugby regulation 6, specifically betting on rugby union.
He has been part of Gatland's highly-successful coaching team since 2008, and is now back in Wales.
Former Wales fly-half Stephen Jones, who was due to succeed Howley as attack specialist after the tournament, will join the squad on Thursday ahead of a World Cup opener against Georgia in Toyota City.
"We were shocked," Gatland said at Wales' squad base in Kitakyushu. "At the moment, these are allegations. Obviously, Rob was devastated by the allegations. That's all I can say.
"The Union are dealing with this, and my focus has to be on the next five days in terms of preparing the squad for the first game against Georgia.
"You have to deal with adversity at times, and it's how you respond and react to that. This has happened.
"I must say that the players in the last 24 hours have really stepped up and they have been incredibly responsible and resilient, and sometimes that brings teams closer together.
"We have got to draw a line in the sand on this, and really focus on preparing the team for the next five days.
"We got a shock the other day, like I said, and it took a bit of time for it to sink in.
"We can't say anything that potentially jeopardises the investigation, and we are pretty aware of that. There was concern by the coaches and the players about Rob and the welfare of Rob.
"Yesterday was my birthday, yes. I have had better birthdays for sure! It's all part of the life experience."
Asked if he had spoken to Howley, Gatland added: "I did text him to say I hope you got home okay, and to see how he was doing."
If found guilty, Howley could face the maximum sanction of a life ban from the sport, with betting on any rugby game outlawed for the likes of players, coaches and match officials, among others.
He is provisionally suspended from any rugby-related activity, pending an investigation the WRU will lead.
Revealing a timeline, Phillips said: "We were contacted on Wednesday of last week informally to suggest there was a potential breach of regulation 6.
"We were then contacted formally with further information on Friday evening. We took Saturday to digest that information.
"It's a pretty serious allegation, and we needed to be confident in our actions if we were going to do anything. That was important.
"Clearly, we are on the eve of the World Cup - the biggest tournament we play in - so that was a factor.
"But, equally, we were very conscious that we needed to act quickly and be decisive. That's exactly what we've done."
Phillips said the initial approach came from a betting company's integrity team, not World Rugby.
He added: "These are serious allegations, there is a lot to cover, people to speak to, data to look at. I wouldn't put any pressure on anyone to do things quickly - I will be putting pressure on them to do it right.
"We are so early on. The investigation hasn't started. We are here, Rob is back in Wales.
"We will start to get under the bonnet of it now. When we start, we will get a sense of how long it's going to take.
"Rob is back in Wales, and we have put the necessary support around him.
"Several of the coaches are in touch with him and we're checking in on his well-being as we formalise our processes to get through the investigation."
Revealing further details of events, Phillips said: "There is probably a distinction between what we were made aware of on Wednesday, which was being asked for some information for the integrity teams to validate that Rob was the person concerned.
"We didn't really see any detail on what the allegation was until Friday evening.
"There is no doubt in my mind that the players and coaches know what regulation 6 is and how it works.
"The Welsh Rugby Players' association, when players first get contracts, put work in in this area. There are online modules players have to complete on a pretty regular basis.
"They get briefings on a regular basis, and they sign to confirm they understand what's required of them on a regular basis, so without a shadow of a doubt I think people in rugby know what's required of them."
Asked if Howley could come back, Phillips added: "I don't have a view on the timing.
"We've made a change and we stick to that change now. Any further instability isn't going to help anybody. We need to accept that rather than predict where it goes. Stephen is here for the duration."