An alleged robber threatened to shoot a police sergeant in the head and tried to choke himself with his underpants in custody, the High Court heard today.
Jamie McCombe also warned officers detaining him that he could get access to guns, it was claimed.
Details emerged as the 20-year-old from Craigyhill in Larne, Co Antrim mounted a fresh bid to be released on bail.
He is charged with three separate cash robberies on a chip shop in his hometown between January and April last year.
McCombe also faces counts of carrying a firearm or imitation firearm with intent to commit robbery and possession of cannabis.
He was previously released on bail to live at an address outside Larne, but was arrested again for another alleged offence of handling a stolen fragrance set earlier this month.
The accused is now further charged with criminal damage to two detention cells at Coleraine PSNI custody suite, assaulting a police officer and threatening to kill him and his family.
Opposing bail, Crown lawyer Natalie Pinkerton claimed: "He threatened to shoot him in the back of the head."
Mr Justice Colton was told McCombe defecated in his cell, smeared it over the walls, and told officers he knew where other weapons are kept.
"There's a very real risk that if released he may carry out these threats," Ms Pinkerton argued.
Defence counsel claimed his client's behaviour in the cells on January 7 was due to mental health issues.
"At one stage he had been given his underwear back and he made an attempt to choke himself," the barrister said.
"The defendant had complained about his treatment by police when he was in custody, in his own words he felt like he was being treated like a dog.
"He was covered in his own urine and faeces, he was in a bad state mentally and he tried to choke himself."
Adjourning the bail hearing, Mr Justice Colton stressed the need for support mechanisms to reduce any risk of re-offending.
He added: "If I was forced to make a ruling today I would refuse the application."