Serial rapist Stephen Charters was given an Order of Lifelong Restriction on June 13.
Now, an investigation has been launched after the 57-year-old’s body was found in the Hermiston Hall at Saughton prison on Saturday evening (June 18).
A prison insider told The Scottish Sun fellow inmates had been “kept in their cells” after Charter’s body was found.
The source said: “We didn’t know what was going on but everyone was in their cells after his body was found.
“We knew it was something serious but no one had a clue.
“Then we found out Charters was dead. He only came in last week.
“There are all sorts of stories doing the rounds but I am not really sure what has happened.”
Another prison insider told the Evening News: “He collapsed in a hall with a suspected massive heart attack. Outside his cell.”
Charters attacked the Edinburgh teenager at hotels in the Capital when she made a cry for help to him and after he earlier preyed on other victims.
A jury had heard Charters claim that sex with the Edinburgh teenager was consensual, but the victim said it made her feel “horrible inside” and she was “just frozen”.
Charters, formerly of Galashiels, said he held “Christian beliefs” and was involved with the church in Edinburgh as a young adult.
The girl he raped in hotels had attended a church in Leven, in Fife, where he acted as a worship leader.
He targeted the girl after she had a row with her boyfriend and appealed to Charters for assistance finding somewhere to stay.
Edinburgh crime news: Survivor of serial rapist Stephen Charters speak out about…
Charters claimed that he hoped to contact her father and take her home. But instead he booked into a hotel and subjected her to sex acts before raping her.
He was convicted last year of nine offences, including rape, sexual assault and indecent conduct towards four victims between November 1984 and October 2015.
He has already served a five year jail term imposed in 2016 for sex crimes against children.
His 2016 trial heard Charters began his crimes as a boy and continued into adulthood.
He had denied the offences but was found guilty of five charges of indecent behaviour and two of rape between 1977 and 1997.
The serial offender carried out sex crimes between 1977 and 1997 in the Borders, Midlothian and Lanarkshire.
He was convicted of sexual offending from the age of 12 – the youngest age for prosecution in Scotland.
Charters began by molesting a younger girl at a house in the Borders, exposing himself and carrying out sex acts from when she was nine. He raped her when she was 11 years old.
He later abused a second girl at a house in Midlothian and at the Royal Commonwealth Pool in Edinburgh before raping her.
Jailing him after the latest convictions, judge Lady Carmichael said Charters had “caused serious and enduring harm.”
She added “You present a high risk of further sexual offending. You have a limited capacity for change.”