The only thing reported was: "A witness has since come forward (since March 24, when the items were found) to say that a man fitting Jonny's description was seen swimming in the river on the afternoon of Tuesday 2nd March." No mention was made of the witness' name or any details.
My guess is that because his family left Richmond almost immediately after his belongings were found, the police must have indicated they felt it very likely JD had taken a swim and drowned and that his bike was simply stolen by someone who later found it abandoned.
JD's belongings were found on March 24 "in a hollow area under a concrete pad" on the bank of/near/beside the river," and consisted of his backpack, "outer clothes," shoes, phone, and "personal items." The police were never completely candid but after reading various accounts it appeared they found everything but his underwear. It was later reported he did not have his passport with him. Even if the sighting of him in the river swimming that day is incorrect, finding JD's clothes tends to suggest an impromptu swim and that he did not leave the area without them. But that is not necessarily the only possibility.
The worst case scenarios are these: accidental drowning, suicide, murdered before dressing after swimming (if he in fact did take a swim), or murdered somewhere, his clothes removed and left at that location. Again, the manner in which his clothes were left seem fairly significant. If foul play was involved it's not likely the culprit would have placed them anywhere carefully, even if he hid them to buy himself some time. If the clothes were lying out as if to be put on again or hidden away more or less neatly, then drowning or a planned disappearance seem the remaining alternatives. If he did choose to ride away from his life, the way he left his clothes might further indicate whether he deliberately staged the appearance of his drowning or just left suddenly on a whim after hiding his clothes. Obviously, that would necessitate his having had other clothes available.
The only hope left seems to be that JD planned his disappearance. The safety camera photo of JD leaving Gladding Residence with his bike doesn't give a great view but seems to indicate that not much was in his backpack at the time the photo was taken. It's somewhat difficult for me to believe a full change of clothes could be stored inside but maybe men are different. However, he could have hidden a change of clothes somewhere ahead of time or even had assistance leaving the area. Looking at what he was wearing as he left on his bike seems inadequate for warmth given the wind chill factor for a bike ride across town.
If JD drowned the scenario would seem to be something like this: On a cold day JD attended class in the morning, left his residence on his bike about 11 a.m., stopped by the 7-11 at Harrison & Main, biked to Belle Isle, a place he frequented, where he spoke to someone on his cell phone. At some point after leaving Belle Isle this young man who was raised near the English Channel and likely well aware of the dangers of hypothermia while swimming, stopped at Rockett's Landing at Dock & Water Streets (an unusual place to take a swim as opposed to Belle Isle where he had earlier been), took off his outer clothes in mid-30's temperatures, possibly in light rain or snow, and got into the cold water, whereupon at some point he drowned. Not being JD, someone close to him, or a "Guernseyman," I have no way of discerning if this is a likely scenario.
Footage includes video of the exact spot his clothes were found:
http://www.wtvr.com/videobeta/?watchId=f39e1dea-c38b-47af-b078-829d5233a8d2
I find it surprising that JD has already been to New York, New Orleans and Austin, TX. (Mode of travel unknown or with whom.) I don't know exactly how long JD has been at VCU but it's been implied that it's been "a year." (School year or calendar year?) In the two days just prior to his disappearance he and a friend back home had emailed about taking a bike trip to FL together in the near future. Then there is the statement a professor made saying that JD came to him a few weeks before expressing concern about his heavy workload. Spring break was coming up March 14-21. Final exams, May 6-15.
His mother's message to him was this: "Johnny, I'm just sending you a message from my heart, because you know the last thing I said to you was to keep safe. We love you so much, everybody's out looking for you. There's a lot of media interest that we don't want to you to be scared of. You can come home to Guernsey ... and take all the time you want and find out what you really want to do in life. Please come home and get in touch with somebody. We love you so much."
Since JD disappeared, four bodies have shown up in the James River reasonably near to Rockett's Landing, all fairly recent cases of people gone missing. Water temperature is increasingly proportional to the speed with which a body tends to rise to the surface, but after four months now, still nothing.
Nothing I speculate on here is meant to impugn in any way the character of this dear young man. If I were a loved one, anything other than his death would be the best of all possible worlds to me, no matter how much pain his action unwittingly caused.