Officers want to hear from anyone who could help identify him.
A woman was also attacked in a separate incident on Leith Way, around 9.15.
She was walking towards UniCol when she was pushed over and sexually assaulted.
He's described as a Caucasian man in his early 20s, 180cm tall with medium build, and having long dark curly hair that was tied back.
Detective Senior Sergeant Kallum Croudis said they were keeping an open mind on whether the attacks were connected.
"A team of 10 staff is investigating these incidents, scene examinations are complete and the large job of scrutinising CCTV footage is under way.
"All three victims are extremely traumatised by what's happened and are receiving strong support.
"Police are conscious of the social media comment regarding these events, but urge anyone who might wish to assist to contact us."
Anyone with information can call police on 03 471 4800, or call Crimestoppers anonymously on 0800 555 111.