Calgary police have laid charges following an assault on Sunday morning that left one man in critical life-threatening condition.

Police were called to a home on Royal Oak Drive in the northwest around 2 a.m. MT.

Officers say they found a man, believed to be in his 60s, in critical condition.

He was taken to hospital by EMS and his condition has not improved.

Given the extent of the victim's condition, police say the homicide unit is leading the investigation.

Shaun Peter Desautels, 42, has been charged with uttering threats and aggravated assault.

His record includes at least six assault convictions since 1995, including a 2008 aggravated assault conviction for choking a 13-year-old relative, for which he was sentenced to three years in jail.

Police say it does not appear to be a random attack, but investigators are not disclosing the relationship between the two men.