The Ministry of Justice has named the prison inmate found dead at HMP Lincoln this week.
As previously reported, police were called to the prison on Greetwell Road at 8.52am on Wednesday, June 6 and HMP Lincoln prisoner Ashley Williams, 27, died in custody.
There will be an independent investigation by the Prisons and Probation Ombudsman.
A post mortem is due to take place following the death, which is being treated as unexplained.
A Prison Service spokesperson at the Ministry of Justice said: “HMP Lincoln prisoner Ashley Williams (DOB 01/03/1991) died in custody on Wednesday 6 June 2018.
“As with all deaths in custody there will be an independent investigation by the Prisons and Probation Ombudsman.
“Our sincere condolences are with Mr Williams’ family and friends at this difficult time.”