A "career criminal" used a prison visit to draw a map leading an associate to a loaded double-barrelled shotgun hidden in bushes close to Parliament House. But his plan was partly undone by a sock left covering the gear stick of a stolen car he allegedly abandoned a month earlier.
Details of the plan, allegedly carried out while Gavin Massey was in the Alexander Maconochie Centre early last year, were revealed during a bail application on Monday.
Massey, 30, was seeking bail in the ACT Magistrates Court on weapons, car theft, and stolen property charges.
Prosecutors opposed bail and said the serial offender had committed crimes with alarming regularity for more than a decade, only stopping when he was in prison.
But the court heard Massey now appeared to have difficulty staying out of trouble while behind bars.
The court heard Massey received a visit from an associate in mid-March, during which he allegedly drew a map leading to a loaded shotgun hidden in bushes on Empire Circuit, just streets away from Parliament House.
The map was then torn up and tossed in the bin, police allege.
Massey's associate went to look for the shotgun, the court heard, but was unable to find it.
Criminal Investigations detectives didn't have the same problem.
A prison officer discovered the map, pulling the pieces from the bin and passing them onto police. Authorities searched near Empire Circuit and found the shotgun, and have obtained CCTV footage of the prison visit.
A number of images of Massey posing near the shotgun were also found by police on his mobile phone, which they seized after arresting the serial crook over the alleged theft of a car.
A sock covering the gear stick - left behind after Massey allegedly abandoned the stolen car in Wanniassa in early February - first led police to the 30-year-old according to a police statement of facts tendered to court.
The prosecution argued Massey ''can't behave whilst on parole, and it seems now he can't even behave while in the Alexander Maconochie Centre''.
The bail application - timed to coincide with his potential release from jail in May this year - was denied by the court.
The defence argued Massey, for the first time in his life, had ''significant responsibility'' in the form of a young baby and a partner in need of care.
It argued he had a job waiting, stable accommodation with his mother, and little history of failing to appear before the courts while on bail.
But the application was ultimately rejected on the grounds that any of those circumstances could change by the time he was potentially able to be freed from jail on parole in May.
Massey will appear in the ACT Magistrates Court again in April.