Police are looking for witnesses who may have seen a B.C. teen before his death, which family and friends say was witnessed by many who chose not to intervene.

Carson Crimeni, a 14-year-old from Langley, died of a suspected overdose at a skate park while witnesses stood by and captured video on their cellphones.

Eventually, a group called 911 after finding Carson unresponsive around 10 p.m. Wednesday. He later died in hospital, and his mother believes it was because somebody gave him drugs.

Dozens gathered for a vigil at the skate park outside the Walnut Grove Community Centre the next night, leaving flowers and lighting candles. Many people hugged and cried as they remembered the teen.

Carson was seen at the skate park in the early afternoon with a group of boys who witnesses say were taunting him and recording video as his condition worsened and he looked increasingly unwell.

Some of those videos were then posted to social media.

"Carson was a really beautiful kid," said his mother, Chantelle Griffiths. "He really was. He was special. He was loving."

Langley RCMP confirm they are investigating the death as an overdose. Serious Crimes investigators are now looking to speak with anyone who may have seen or interacted with the teen before he died.

Police believe Carson was in several areas including Walnut Grove Secondary School and Walnut Grove Athletic Park in the hours before he went into medical distress. RCMP say he may have been in the area as early as noon on Wednesday.

Carson's father, Aron Crimeni, says he was uplifted by the show of support at Thursday night's vigil, calling his son's death a tragedy.

"Even just the smallest thought that a call to 911 a couple hours earlier could have changed the whole story is devastating. It really is," Aron told reporters. "I just would expect when people see somebody in danger to do something to help them."

Aron says he is hopeful people who did not try to assist his son will be held accountable.

"He was my best friend," he said as he wiped away tears.

Friends and family have started a GoFundMe page in Carson's memory.

At this point, doctors who treated Carson haven't been able to tell his parents what he ingested that could have contributed to his death.

The BC Coroners Service is investigating, along with Langley RCMP and the Independent Investigations Office.

An email sent to Walnut Grove Secondary School students' families described the teenager as an "important member" of the community, and urged parents to discuss the tragedy with their children.

"We cannot anticipate how far-reaching the impact of this news may be on staff and students," it read. "Recognizing that this is difficult subject matter to discuss with your child, we ask for families to share this news with their children. It is important that each family handle this with their child in their own unique way."

At Thursday's vigil, RCMP pulled a group of Carson's friends aside to speak with them.

Anyone with information is asked to call Langley RCMP at 604-532-3200.

"Please assist investigators to piece together the tragic last hours of this young man's life," Cpl. Holly Largy said in a statement.

Mounties set up a 24-hour tipline for anyone with more information on the case. Tips can be left at 604-532-3398.

With files from CTV News Vancouver's Ben Miljure and Jon Woodward

Update Aug. 10: On Saturday, the IIO released a statement explaining the reasons for its involvement in the case.

"The reason the IIO is involved is due to the fact that police were in the area around the time the young man was suffering from the issues that led to his death. We are investigating to determine whether any action or inaction on the part of the police played a role in his death," the statement read.

"In all cases of which we are notified, the IIO investigates specifically to determine whether the actions or inactions of police may have been a contributory cause of serious harm or death," the office said. "We do not require a specific allegation of wrongdoing. If we find there was such an action or inaction, we will then determine whether there are reasonable grounds to believe an offence was committed by a police officer."