A fourth person has been arrested following a carjacking and crime spree in Hamilton, and police say there may be more victims out there.

The victims included two women in their 80s, a woman in her 70s, and a 12-year-old boy, who were robbed during incidents that began on Tuesday, Apr. 18.

In three cases, seniors were either carjacked or robbed in their cars in the parking lot of shopping plazas around the city.

In another case, the 12-year-old was robbed at gunpoint while walking.

Police announced three arrests on Tuesday and on Wednesday, announced a fourth.

An 18-year-old Hamilton man was arrested and charged with two counts of robbery and two counts of pointing a firearm.

Police said yesterday that an imitation pellet pistol was believed to have been used in the robberies.

The investigators say they believe there may be similar incidents that have happened in the city that haven't been reported yet.

Anyone with information is asked to contact police at 905-546-8927.