`Caniço went missing on the night of 21 June at a riverside techno festival in Nantes, western France, for the annual nationwide Fête de la Musique.
Police moved in to disperse fans in the early hours, saying the music had exceeded the set time. According to witnesses, police charged using tear gas and rubber bullets to break up the party.
During the clashes, 14 people fell into the river and were rescued by firefighters. But it was only on Monday this week - 38 days later - that the body of 24-year-old Caniço was retrieved. It was identified the following day.
The police carried out their own internal inquiry (via the IGPN) into what happened. Prime Minister Edouard Philippe on Tuesday announced that the investigation had found no evidence of a link between the security forces' intervention and Caniço’s disappearance.
He did, however, acknowledge that many questions remained over how the event had been handled.
"More than five weeks after the events, what happened that night remains unclear and I am not satisfied," he said.
He promised “total transparency” and the interior ministry’s own investigative body (IGA) will now open its own inquiry. It's expected to deliver its conclusions in a month's time.
Family and friends of Steve Caniço refute the police enquiry's findings and have been demonstrating in Nantes under the banner "Justice for Steve".
On Tuesday night they gathered in Nantes to light candles along the River Loire close to where he died. Many were angry.
"There’s anger because the internal police enquiry said there was no link between Steve's death and the police charge," said Alexane, a close friend of Caniço's.
"That's a bit ironic when you know that the last person to see him was 10 minutes before the police charged and that he was sleeping. I don’t see how it’s possible that there isn’t a link.
"What's happening is unbelievable. For Steve's friends and family, if no one admits what happened there will always be bitterness.”
Nelly, a mother of four, was also there to express her anger.
"My 24-year old daughter saw everything. These youngsters did nothing wrong and they weren't bothering anyone," she told RFI. "Ok, they over-ran by half an hour, big deal. You should be able to talk it through. But no! Immediately there's confrontation."
The police maintain that they did not charge the music festival and said officers were being targeted by people throwing various objects.
But charge or no charge, journalist Jonathan Bouchet-Petersen questioned the police's methods.
"The massive use of teargas (33 canisters pulled in 32 minutes), the low visibility on the river banks at 4:30 am on the night of Fête de la Musique with tipsy party-goers; this is key to understanding what happened," he tweeted.
A more independent enquiry?
Several commentators have highlighted that the internal IGPN enquiry was far from independent.
"Last year it was called on to investigate 612 cases involving deliberate acts of police violence and not a single prosecution has resulted," wrote Jean-Marcel Bouguereau in La République des Pyrénées.
“What matters is to provide full transparency," interior minister Christophe Castaner said on Wednesday. "The demand for transparency and truth is what the family and the French public wants and it's legitimate."
Transparency is not quite the same as independence, but the IGA enquiry is indeed broader in scope, bringing in the police prefecture, the city council and private organisers involved in the music festival.
It will look into whether the prefect had any responsibility in what happened, what orders were given to the police to stop the music and whether the local council should have allowed a concert on the riverbanks without protection barriers.
Important questions no doubt, but the key one remains whether Steve Caniço, whom friends say did not know how to swim, might still be alive had the police not intervened.
FÊTE DE LA MUSIQUE : DES IMAGES DES VIOLENCESNantes Révoltée (@Nantes_Revoltee) June 23, 2019
Des milliers de nantais et de nantaises ont vécu des violences inacceptables le soir de la fête de la musique à Nantes. Coups, arrestations, gaz, et chutes dans la Loire. Quelques images captées par un lecteur. pic.twitter.com/R6H4WmDNAb
Footage shared on social media showed police armed with batons and riot shields moving in on the banks of the Loire, clearly contradicting the IGPN report's conclusions.
Prosecutors have opened an investigation for possible manslaughter.
Ongoing anger over police methods
Anger over Steve Caniço's death comes on the back of growing mistrust between the French and their police force.
Police are already under fire for heavy-handed interventions during the weekly Yellow Vest anti-government protests that began last November. Around 30 protesters have lost eyes or hands during clashes with police over the past six months.
In late June, interior minister Castaner called for an investigation after riot police teargassed environmental campaigners in Paris.
And there's the ongoing case of Adama Traoré, 24, who died in police custody in 2016 in what his family maintain was a racially-motivated case of police brutality.
The methods used by the French police force have been criticised by a number of international organisations including the UN and the European parliament.
Eric Coquerel, an MP with hard-left France Unbowed, has called for a parliamentary enquiry telling RFI the police intervention was "disproportionate" and "dangerous" given the closeness of the river.
"For months now we've been living in a climate where part of the police force simply does what it wants with the government's backing. We were all afraid a tragedy would happen and it feels like it has."
Several left-wing MPs have gone further and are calling for the interior minister to resign. The prime minister says Castaner has his "full support". For the moment.