A Cape Breton mother is demanding answers from police after her 17-year-old son was killed by a vehicle leaving a prom party, and no charges were laid against the driver seen by a witness with alcohol in his hand.

A voicemail left on Joneil Hanna’s friend’s cellphone at 3:23 a.m. on June 10 captured the frantic moments as partygoers attempted to help him after he was struck.

“Joneil! Joneil it's me. You killed him,” the voicemail begins. “Joneil bro. Put him in the car, come on. We can't lift him. We can't lift him! Yes we can.”

Police said they responded to a report of a man on Highway 223 in Leitches Creek, N.S., 14 minutes after that call was made. Officers said the driver of the vehicle that struck Hanna attended the party and remained at the scene.

“The officers that did speak with him at the scene of the accident determined that there was no need to read him the breathalyzer demand,” Cape Breton Regional Police Staff Sgt. Bill Turner told CTV Atlantic on Wednesday.

One of the partygoers, Josh Barrie, said he spotted the driver at the party prior to the incident.

“I was up by the white tent up in Leitches Creek at the prom party, and saw the driver go by with liquor in his hand, following his girlfriend,” said Barrie.

Hanna’s mother Jennifer said she can’t understand why police have not held anyone accountable for her son’s death.

“I think that they are doing all that they can,” she said. “But I also think that there is something they are not doing, and something they are hiding.”

No charges have been laid. Police determined the driver was not impaired at the time of Hanna’s death. He was questioned later that day.

Staff Sgt. Turner said the decision not to administer a roadside sobriety test was based on police observations at the scene.

“People can consume alcohol and not be impaired,” he said.

The voicemail is a chilling reminder of what happened on the road that night. Hanna’s friend Matthew Kavanaugh received the recording on his cellphone. He said listening to message was incredibly painful.

“I just got sick to my stomach,” he said. “You don’t really expect to get a message like that on voicemail.”

A GoFundMe crowdfunding page has been set up to support the family.