Darran Everett, 25, left his home in Musselburgh, East Lothian, on October 12 - a week before he was due to become a father for the second time.
His body was discovered by a member of the public the following day, though he as not immediately identified.
Mr Everett’s partner had contacted Police Scotland on several occasions between October 12 and October 14 to report that he had not returned home. On the third call, she expressed concern for his welfare.
A report by the Police Investigations & Review Commissioner (PIRC) found that police had failed to record a “report for concern”.
The report said Mr Everett had been arrested on October 10 after causing a disturbance in the grounds of Edinburgh Royal Infirmary. He was taken to St Leonard’s police station, where he told police staff he was suicidal and a Vulnerability Assessment Form was filled out. He appeared at court on October 11 and was released on bail.
The report said he returned to his partner’s flat on October 12 and was last see at 7pm before leaving the flat.
“His partner phoned police at 2316 hours when he failed to return and asked if he was in custody. She was told that he had not been arrested and she did not report him missing at that time.”
The report said she phoned again the following morning and the police told her he had been in custody earlier in the week and may have been remanded in prison. The call handler advised her to contact Mr Everett’s solicitor and incorrectly told her he was safe and well.
On October 14 Mr Everett’s partner phoned police again to say he had now been missing for 48 hours. She said the solicitor had confirmed he had not been remanded to prison and she now wanted to report him as a vulnerable missing person.
Mr Everett’s body had already been discovered, but despite a distinctive tattoo on his abdomen he had not been identified.
The report said while his partner was on the phone, Mr Everett’s brother also contacted Police Scotland to report his concerns.
“He provided a description which included a distinctive Ninja tattoo on his stomach. As a result, a ‘concern for person’ incident was raised and transferred to the Area Control Room which resulted in the body found at Musselburgh Harbour being identified as that of [Mr Everett].”
A post mortem determined Mr Everett had died from drowning.
The PIRC report also said Police Scotland custody staff did not correctly complete the G4S Personal Escort Record form to highlight that the man was suicidal or at risk of self-harm prior to his transfer to G4S.
Chief Superintendent Mark Hargreaves of the Professional Standards Department said: “Police Scotland recognises the findings of the PIRC’s report and can confirm the service has reviewed its process for dealing with calls about people in custody and has circulated a revised process to address this matter. Our thoughts remain with the family of the man who tragically died.”
Join our Facebook group Our Edinburgh to share images and news from and around the Capital