A legal expert is weighing on the controversial decision by police in Cape Breton to not administer a breathalyzer to the driver in an incident that killed a 17-year-old boy after a grad party.

Meanwhile, family and friends of Joneil Hanna are planning a rally this weekend as they say they continue to seek justice.

Joneil’s mother, Jenn Hanna, will wear a black ribbon on her chest at a rally this weekend for her 17-year-old son.

“It's a peaceful rally,” she said Friday. “We just want justice for my son.”

The Memorial High School student was struck and killed by a vehicle in the early morning hours of June 10. His mother says he had been attending a grad party just down the road.

Cape Breton Regional Police confirm the driver was at the party, but say there was no evidence to indicate he was impaired at the time of Joneil's death.

“I'm not going to let it go down easily,” Jenn Hanna said.  “I'm going to make sure that my son does get justice.”

One of the main questions Hanna and others have is why the driver wasn't given a breathalyzer test.

Wayne MacKay is a professor emeritus at Dalhousie’s Schulich School of Law.

He says many people might not realize that police can't give the breathalyzer unless they have reasonable grounds to do so.

“Before a police officer can give the breathalyzer, they have to be able to justify their concern or suspicion about impairment,” MacKay says. “So they have to think there’s some evidence that the person is impaired by alcohol.”

MacKay says such evidence could include slurred speech, glassy eyes, or the smell of alcohol.

He admits in this case, without knowing all of the evidence, it's surprising there wasn't enough reason to give the test.

“There's certainly some things, looking from the outside,” MacKays says. “It was obviously a heavy drinking party going on here. These people -- I guess they knew that they had left from that party, so it would seem to be a reasonable concern that ‘maybe, you too have had alcohol.’”

MacKay says while it's too late to second-guess the breathalyzer decision, police could still charge someone in this case. A day after laying her son to rest, a heartbroken Jenn Hanna says she simply wants justice and closure.

“I feel that if people are going to be rallying for my son, I should be there to let them see me, and how it is affecting me,” she said.

The rally will be held in front of the police station in Sydney Mines.It is scheduled for 2 p.m. on Sunday.

When contacted Friday, Cape Breton Regional Police said they had nothing new to add.

Earlier this week, police said their decision to not request a breathalyzer was based on first-hand observations from several officers at the scene.

With files from CTV Atlantic’s Ryan MacDonald.