The offender was travelling north on State Highway 1 when police tried to pull him over about 12.30pm. A pursuit was called off when his speeds exceeded 170km/h.
After he got stuck in traffic coming off the Takanini/Manurewa off-ramp, the man abandoned his car, pointed his gun at police and walked to the top of the row of traffic - where he spotted Mr Colmer's car.
The gunman opened the passenger door and got in.
Police said the gunman ran into a family member's house. He was caught when he tried to flee the house.
Yesterday, a 45-year-old Waikato man appeared in the Manukau District Court on six charges. He did not enter any pleas and was remanded in custody. The most serious charges were kidnapping and using a firearm against the police. He was also accused of unlawfully possessing an AK-47 rifle.