Police in the Halifax area are investigating a fourth case of a pin being placed inside a candy bar handed out on Halloween.

Halifax police say the latest pin was discovered Thursday evening by a parent who took a bite of a small candy bar.

Police say the bar was handed out in the Joseph Howe Drive and Bayers Road area of Halifax.

They are investigating two other complaints of pins found inside candy bars handed out in a Cole Harbour neighbourhood and another case in the Portland Estates area of Dartmouth.

“They’ve all involved Halloween-sized mini chocolate bars,” says Halifax Regional Police Const. Dianne Woodworth. “The pins have been located in the chocolate bars. All the incidents stem from Halloween night.”

People who live in the west-end Halifax neighbourhood where the latest pin was found say they are dismayed that someone would tamper with Halloween candy.

“It’s kind of surprising that people would even do that,” says Sheila MacNeil.

“It’s concerning. I had grandchildren trick-or-treating on this street and I asked all their mothers to check all their chocolate bars,” says Laurie MacKay.

Police say they can’t comment on the implications of the pins being found in a wide area, from Cole Harbour to west-end Halifax.

Halifax Regional Police and Halifax District RCMP say they have merged their investigations.

“The integrated general investigation section is investigating all of these complaints so that they will be looking at a number of different avenues as they pursue the investigations collectively,’ says Halifax District RCMP Cpl. Greg Church.

“We do have physical evidence. We also have evidence from the teenagers where they went trick-or-treating.”

Two cases of candy tampering have also been reported in the Cape Breton Regional Municipality.

A mother in Sydney Mines contacted police Thursday evening after her son discovered a silver pin inside a candy bar he had been eating.

Cape Breton Regional Police say the boy had been trick-or-treating on Demarco Street, Ocean Street, Atlantic Street, George’s River Road and Lannigans Lane.

A family in North Sydney contacted police Monday evening after someone bit into a chocolate bar and found a sewing needle inside. Police say the bar was collected in the Pierce Street area of North Sydney.

Investigators are cautioning parents to check their children's candy.

With files from CTV Atlantic's Ron Shaw